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Chapter 1: Real Numbers

NCERT Solutions for CBSE Class 10 Mathematics — 199 solved questions with detailed explanations.

199
Questions
5
Topics

Important Formulas

Solved Questions

Q1. In Euclid's division lemma a = bq + r, the constraint on r is:

Difficulty: Easy · Topic: Euclid's Division Lemma

Solution

By definition, the remainder r satisfies 0 ≤ r < b. It can be 0 (exact division) but must be strictly less than the divisor b.

Q2. The prime factorisation of 3825 is:

Difficulty: Easy · Topic: Fundamental Theorem of Arithmetic

Solution

3825 ÷ 3 = 1275; 1275 ÷ 3 = 425; 425 ÷ 5 = 85; 85 ÷ 5 = 17 (prime).

3825 = 3² × 5² × 17

Q3. Find the HCF of 867 and 255 using Euclid's algorithm.

Difficulty: Easy-Medium · Topic: Euclid's Division Algorithm

Solution

867 = 255 × 3 + 102

255 = 102 × 2 + 51

102 = 51 × 2 + 0

HCF = 51

Q4. Find HCF of 4052 and 12576.

Difficulty: Easy-Medium · Topic: Euclid's Division Algorithm

Solution

12576 = 4052 × 3 + 420

4052 = 420 × 9 + 272

420 = 272 × 1 + 148

272 = 148 × 1 + 124

148 = 124 × 1 + 24

124 = 24 × 5 + 4

24 = 4 × 6 + 0

HCF = 4

Q5. Find LCM and HCF of 306 and 657 by prime factorisation and verify HCF × LCM = product.

Difficulty: Easy-Medium · Topic: Fundamental Theorem of Arithmetic

Solution

306 = 2 × 3² × 17; 657 = 3² × 73

HCF = 3² = 9; LCM = 2 × 3² × 17 × 73 = 22338

9 × 22338 = 201042 = 306 × 657 ✓

Q6. Which has a terminating decimal expansion?

Difficulty: Easy-Medium · Topic: Rational Numbers and Decimal Expansions

Solution

3125 = 5⁵ (form 2ⁿ5ᵐ) → terminating. Others have prime factors besides 2 and 5.

Q7. Write the decimal expansion of 17/8 without actual division.

Difficulty: Easy-Medium · Topic: Rational Numbers and Decimal Expansions

Solution

8 = 2³. Multiply: 17×5³/(2³×5³) = 17×125/1000 = 2125/1000 = 2.125

Q8. If HCF(a,b) = 12 and a×b = 1800, then LCM(a,b) is:

Difficulty: Easy-Medium · Topic: Euclid's Division Lemma

Solution

HCF × LCM = a × b → 12 × LCM = 1800 → LCM = 150

Q9. Which is irrational?

Difficulty: Easy-Medium · Topic: Irrational Numbers

Solution

√4=2, √18/√2=3, √12×√3=6 — all rational. √5−3 is irrational (irrational minus rational).

Q10. 33/(2²×5) terminates after how many decimal places?

Difficulty: Easy-Medium · Topic: Rational Numbers and Decimal Expansions

Solution

33/20 = 165/100 = 1.65 → 2 decimal places. Rule: max(n,m) where denom = 2ⁿ×5ᵐ → max(2,1)=2.

Q11. Find the HCF of 119 and 178.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 119 and 178:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(119, 178) = 1\)

Q12. Find the HCF of 249 and 120.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 249 and 120:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(249, 120) = 3\)

Q13. Find the HCF of 54 and 258.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 54 and 258:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(54, 258) = 6\)

Q14. Find the HCF of 257 and 285.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 257 and 285:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(257, 285) = 1\)

Q15. Find the HCF of 93 and 187.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 93 and 187:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(93, 187) = 1\)

Q16. Find the HCF of 233 and 272.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 233 and 272:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(233, 272) = 1\)

Q17. Find the HCF of 221 and 257.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 221 and 257:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(221, 257) = 1\)

Q18. Find the HCF of 66 and 69.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 66 and 69:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(66, 69) = 3\)

Q19. Find the HCF of 24 and 257.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 24 and 257:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(24, 257) = 1\)

Q20. Find the HCF of 70 and 69.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 70 and 69:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(70, 69) = 1\)

Q21. Find the HCF of 36 and 83.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 36 and 83:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(36, 83) = 1\)

Q22. Find the HCF of 210 and 119.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 210 and 119:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(210, 119) = 7\)

Q23. Find the HCF of 215 and 52.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 215 and 52:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(215, 52) = 1\)

Q24. Find the HCF of 45 and 94.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 45 and 94:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(45, 94) = 1\)

Q25. Find the HCF of 234 and 136.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 234 and 136:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(234, 136) = 2\)

Q26. Find the HCF of 96 and 220.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 96 and 220:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(96, 220) = 4\)

Q27. Find the HCF of 37 and 131.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 37 and 131:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(37, 131) = 1\)

Q28. Find the HCF of 101 and 35.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 101 and 35:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(101, 35) = 1\)

Q29. Find the HCF of 283 and 226.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 283 and 226:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(283, 226) = 1\)

Q30. Find the HCF of 241 and 58.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 241 and 58:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(241, 58) = 1\)

Q31. Find the HCF of 114 and 80.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 114 and 80:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(114, 80) = 2\)

Q32. Find the HCF of 65 and 150.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 65 and 150:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(65, 150) = 5\)

Q33. Find the HCF of 167 and 261.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 167 and 261:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(167, 261) = 1\)

Q34. Find the HCF of 187 and 54.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 187 and 54:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(187, 54) = 1\)

Q35. Find the HCF of 107 and 78.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 107 and 78:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(107, 78) = 1\)

Q36. Find the HCF of 181 and 54.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 181 and 54:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(181, 54) = 1\)

Q37. Find the HCF of 96 and 248.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 96 and 248:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(96, 248) = 8\)

Q38. Find the HCF of 146 and 254.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 146 and 254:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(146, 254) = 2\)

Q39. Find the HCF of 87 and 282.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 87 and 282:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(87, 282) = 3\)

Q40. Find the HCF of 48 and 164.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 48 and 164:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(48, 164) = 4\)

Q41. Find the LCM of 52 and 7.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(52,7) = 364\) ... wait, let's compute:

\(\text{LCM}(52,7) = \frac{52 \times 7}{\text{HCF}(52,7)} = 364\)

Q42. Find the LCM of 10 and 35.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(10,35) = 70\) ... wait, let's compute:

\(\text{LCM}(10,35) = \frac{10 \times 35}{\text{HCF}(10,35)} = 70\)

Q43. Find the LCM of 42 and 33.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(42,33) = 462\) ... wait, let's compute:

\(\text{LCM}(42,33) = \frac{42 \times 33}{\text{HCF}(42,33)} = 462\)

Q44. Find the LCM of 37 and 56.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(37,56) = 2072\) ... wait, let's compute:

\(\text{LCM}(37,56) = \frac{37 \times 56}{\text{HCF}(37,56)} = 2072\)

Q45. Find the LCM of 12 and 17.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(12,17) = 204\) ... wait, let's compute:

\(\text{LCM}(12,17) = \frac{12 \times 17}{\text{HCF}(12,17)} = 204\)

Q46. Find the LCM of 49 and 59.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(49,59) = 2891\) ... wait, let's compute:

\(\text{LCM}(49,59) = \frac{49 \times 59}{\text{HCF}(49,59)} = 2891\)

Q47. Find the LCM of 31 and 45.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(31,45) = 1395\) ... wait, let's compute:

\(\text{LCM}(31,45) = \frac{31 \times 45}{\text{HCF}(31,45)} = 1395\)

Q48. Find the LCM of 53 and 6.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(53,6) = 318\) ... wait, let's compute:

\(\text{LCM}(53,6) = \frac{53 \times 6}{\text{HCF}(53,6)} = 318\)

Q49. Find the LCM of 10 and 36.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(10,36) = 180\) ... wait, let's compute:

\(\text{LCM}(10,36) = \frac{10 \times 36}{\text{HCF}(10,36)} = 180\)

Q50. Find the LCM of 26 and 26.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(26,26) = 26\) ... wait, let's compute:

\(\text{LCM}(26,26) = \frac{26 \times 26}{\text{HCF}(26,26)} = 26\)

Q51. Find the LCM of 32 and 38.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(32,38) = 608\) ... wait, let's compute:

\(\text{LCM}(32,38) = \frac{32 \times 38}{\text{HCF}(32,38)} = 608\)

Q52. Find the LCM of 55 and 49.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(55,49) = 2695\) ... wait, let's compute:

\(\text{LCM}(55,49) = \frac{55 \times 49}{\text{HCF}(55,49)} = 2695\)

Q53. Find the LCM of 6 and 12.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(6,12) = 12\) ... wait, let's compute:

\(\text{LCM}(6,12) = \frac{6 \times 12}{\text{HCF}(6,12)} = 12\)

Q54. Find the LCM of 18 and 12.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(18,12) = 36\) ... wait, let's compute:

\(\text{LCM}(18,12) = \frac{18 \times 12}{\text{HCF}(18,12)} = 36\)

Q55. Find the LCM of 19 and 15.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(19,15) = 285\) ... wait, let's compute:

\(\text{LCM}(19,15) = \frac{19 \times 15}{\text{HCF}(19,15)} = 285\)

Q56. Find the LCM of 31 and 22.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(31,22) = 682\) ... wait, let's compute:

\(\text{LCM}(31,22) = \frac{31 \times 22}{\text{HCF}(31,22)} = 682\)

Q57. Find the LCM of 28 and 39.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(28,39) = 1092\) ... wait, let's compute:

\(\text{LCM}(28,39) = \frac{28 \times 39}{\text{HCF}(28,39)} = 1092\)

Q58. Find the LCM of 40 and 38.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(40,38) = 760\) ... wait, let's compute:

\(\text{LCM}(40,38) = \frac{40 \times 38}{\text{HCF}(40,38)} = 760\)

Q59. Find the LCM of 47 and 17.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(47,17) = 799\) ... wait, let's compute:

\(\text{LCM}(47,17) = \frac{47 \times 17}{\text{HCF}(47,17)} = 799\)

Q60. Find the LCM of 45 and 10.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(45,10) = 90\) ... wait, let's compute:

\(\text{LCM}(45,10) = \frac{45 \times 10}{\text{HCF}(45,10)} = 90\)

Q61. Find the LCM of 42 and 26.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(42,26) = 546\) ... wait, let's compute:

\(\text{LCM}(42,26) = \frac{42 \times 26}{\text{HCF}(42,26)} = 546\)

Q62. Find the LCM of 20 and 55.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(20,55) = 220\) ... wait, let's compute:

\(\text{LCM}(20,55) = \frac{20 \times 55}{\text{HCF}(20,55)} = 220\)

Q63. Find the LCM of 27 and 44.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(27,44) = 1188\) ... wait, let's compute:

\(\text{LCM}(27,44) = \frac{27 \times 44}{\text{HCF}(27,44)} = 1188\)

Q64. Find the LCM of 11 and 28.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(11,28) = 308\) ... wait, let's compute:

\(\text{LCM}(11,28) = \frac{11 \times 28}{\text{HCF}(11,28)} = 308\)

Q65. Find the LCM of 24 and 38.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(24,38) = 456\) ... wait, let's compute:

\(\text{LCM}(24,38) = \frac{24 \times 38}{\text{HCF}(24,38)} = 456\)

Q66. Find the LCM of 6 and 59.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(6,59) = 354\) ... wait, let's compute:

\(\text{LCM}(6,59) = \frac{6 \times 59}{\text{HCF}(6,59)} = 354\)

Q67. Find the LCM of 57 and 23.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(57,23) = 1311\) ... wait, let's compute:

\(\text{LCM}(57,23) = \frac{57 \times 23}{\text{HCF}(57,23)} = 1311\)

Q68. Find the LCM of 46 and 18.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(46,18) = 414\) ... wait, let's compute:

\(\text{LCM}(46,18) = \frac{46 \times 18}{\text{HCF}(46,18)} = 414\)

Q69. Find the LCM of 39 and 54.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(39,54) = 702\) ... wait, let's compute:

\(\text{LCM}(39,54) = \frac{39 \times 54}{\text{HCF}(39,54)} = 702\)

Q70. Find the LCM of 10 and 26.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(10,26) = 130\) ... wait, let's compute:

\(\text{LCM}(10,26) = \frac{10 \times 26}{\text{HCF}(10,26)} = 130\)

Q71. Find the HCF of 80 and 30.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 80 and 30:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(80, 30) = 10\)

Q72. Find the HCF of 148 and 216.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 148 and 216:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(148, 216) = 4\)

Q73. Find the HCF of 49 and 58.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 49 and 58:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(49, 58) = 1\)

Q74. Find the HCF of 169 and 65.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 169 and 65:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(169, 65) = 13\)

Q75. Find the HCF of 206 and 91.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 206 and 91:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(206, 91) = 1\)

Q76. Find the HCF of 160 and 287.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 160 and 287:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(160, 287) = 1\)

Q77. Find the HCF of 198 and 177.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 198 and 177:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(198, 177) = 3\)

Q78. Find the HCF of 113 and 238.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 113 and 238:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(113, 238) = 1\)

Q79. Find the HCF of 130 and 56.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 130 and 56:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(130, 56) = 2\)

Q80. Find the HCF of 39 and 59.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 39 and 59:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(39, 59) = 1\)

Q81. Find the HCF of 213 and 198.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 213 and 198:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(213, 198) = 3\)

Q82. Find the HCF of 112 and 115.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 112 and 115:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(112, 115) = 1\)

Q83. Find the HCF of 222 and 217.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 222 and 217:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(222, 217) = 1\)

Q84. Find the HCF of 24 and 228.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 24 and 228:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(24, 228) = 12\)

Q85. Find the HCF of 274 and 39.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 274 and 39:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(274, 39) = 1\)

Q86. Find the HCF of 196 and 220.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 196 and 220:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(196, 220) = 4\)

Q87. Find the HCF of 55 and 61.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 55 and 61:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(55, 61) = 1\)

Q88. Find the HCF of 224 and 126.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 224 and 126:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(224, 126) = 14\)

Q89. Find the HCF of 29 and 90.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 29 and 90:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(29, 90) = 1\)

Q90. Find the HCF of 132 and 111.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 132 and 111:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(132, 111) = 3\)

Q91. Find the HCF of 182 and 255.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 182 and 255:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(182, 255) = 1\)

Q92. Find the HCF of 294 and 79.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 294 and 79:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(294, 79) = 1\)

Q93. Find the HCF of 46 and 178.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 46 and 178:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(46, 178) = 2\)

Q94. Find the HCF of 238 and 155.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 238 and 155:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(238, 155) = 1\)

Q95. Find the HCF of 112 and 74.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 112 and 74:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(112, 74) = 2\)

Q96. Find the HCF of 212 and 173.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 212 and 173:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(212, 173) = 1\)

Q97. Find the HCF of 249 and 56.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 249 and 56:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(249, 56) = 1\)

Q98. Find the HCF of 249 and 129.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 249 and 129:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(249, 129) = 3\)

Q99. Find the HCF of 186 and 297.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 186 and 297:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(186, 297) = 3\)

Q100. Find the HCF of 113 and 283.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 113 and 283:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(113, 283) = 1\)

Q101. Find the HCF of 296 and 192.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 296 and 192:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(296, 192) = 8\)

Q102. Find the HCF of 78 and 80.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 78 and 80:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(78, 80) = 2\)

Q103. Find the HCF of 39 and 233.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 39 and 233:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(39, 233) = 1\)

Q104. Find the HCF of 281 and 256.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 281 and 256:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(281, 256) = 1\)

Q105. Find the HCF of 249 and 27.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 249 and 27:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(249, 27) = 3\)

Q106. Find the HCF of 28 and 43.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 28 and 43:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(28, 43) = 1\)

Q107. Find the HCF of 149 and 197.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 149 and 197:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(149, 197) = 1\)

Q108. Find the HCF of 58 and 198.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 58 and 198:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(58, 198) = 2\)

Q109. Find the HCF of 54 and 276.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 54 and 276:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(54, 276) = 6\)

Q110. Find the HCF of 91 and 299.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 91 and 299:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(91, 299) = 13\)

Q111. Find the HCF of 156 and 123.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 156 and 123:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(156, 123) = 3\)

Q112. Find the HCF of 57 and 156.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 57 and 156:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(57, 156) = 3\)

Q113. Find the HCF of 48 and 179.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 48 and 179:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(48, 179) = 1\)

Q114. Find the HCF of 83 and 216.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 83 and 216:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(83, 216) = 1\)

Q115. Find the HCF of 74 and 150.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 74 and 150:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(74, 150) = 2\)

Q116. Find the HCF of 198 and 244.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 198 and 244:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(198, 244) = 2\)

Q117. Find the HCF of 274 and 281.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 274 and 281:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(274, 281) = 1\)

Q118. Find the HCF of 40 and 49.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 40 and 49:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(40, 49) = 1\)

Q119. Find the HCF of 270 and 267.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 270 and 267:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(270, 267) = 3\)

Q120. Find the HCF of 166 and 49.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 166 and 49:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(166, 49) = 1\)

Q121. Find the HCF of 249 and 80.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 249 and 80:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(249, 80) = 1\)

Q122. Find the HCF of 255 and 271.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 255 and 271:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(255, 271) = 1\)

Q123. Find the HCF of 51 and 253.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 51 and 253:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(51, 253) = 1\)

Q124. Find the HCF of 84 and 98.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 84 and 98:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(84, 98) = 14\)

Q125. Find the HCF of 159 and 74.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 159 and 74:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(159, 74) = 1\)

Q126. Find the HCF of 162 and 288.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 162 and 288:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(162, 288) = 18\)

Q127. Find the HCF of 25 and 251.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 25 and 251:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(25, 251) = 1\)

Q128. Find the HCF of 95 and 81.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 95 and 81:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(95, 81) = 1\)

Q129. Find the HCF of 239 and 196.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 239 and 196:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(239, 196) = 1\)

Q130. Find the HCF of 241 and 104.

Difficulty: Easy-Medium · Topic: HCF using Euclid's Division

Solution

Using Euclid's division algorithm to find HCF of 241 and 104:

We repeatedly divide the larger by the smaller and take remainders.

\(\text{HCF}(241, 104) = 1\)

Q131. Find the LCM of 46 and 11.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(46,11) = 506\) ... wait, let's compute:

\(\text{LCM}(46,11) = \frac{46 \times 11}{\text{HCF}(46,11)} = 506\)

Q132. Find the LCM of 12 and 58.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(12,58) = 348\) ... wait, let's compute:

\(\text{LCM}(12,58) = \frac{12 \times 58}{\text{HCF}(12,58)} = 348\)

Q133. Find the LCM of 55 and 29.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(55,29) = 1595\) ... wait, let's compute:

\(\text{LCM}(55,29) = \frac{55 \times 29}{\text{HCF}(55,29)} = 1595\)

Q134. Find the LCM of 46 and 17.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(46,17) = 782\) ... wait, let's compute:

\(\text{LCM}(46,17) = \frac{46 \times 17}{\text{HCF}(46,17)} = 782\)

Q135. Find the LCM of 14 and 40.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(14,40) = 280\) ... wait, let's compute:

\(\text{LCM}(14,40) = \frac{14 \times 40}{\text{HCF}(14,40)} = 280\)

Q136. Find the LCM of 12 and 48.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(12,48) = 48\) ... wait, let's compute:

\(\text{LCM}(12,48) = \frac{12 \times 48}{\text{HCF}(12,48)} = 48\)

Q137. Find the LCM of 49 and 23.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(49,23) = 1127\) ... wait, let's compute:

\(\text{LCM}(49,23) = \frac{49 \times 23}{\text{HCF}(49,23)} = 1127\)

Q138. Find the LCM of 38 and 34.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(38,34) = 646\) ... wait, let's compute:

\(\text{LCM}(38,34) = \frac{38 \times 34}{\text{HCF}(38,34)} = 646\)

Q139. Find the LCM of 20 and 8.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(20,8) = 40\) ... wait, let's compute:

\(\text{LCM}(20,8) = \frac{20 \times 8}{\text{HCF}(20,8)} = 40\)

Q140. Find the LCM of 42 and 53.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(42,53) = 2226\) ... wait, let's compute:

\(\text{LCM}(42,53) = \frac{42 \times 53}{\text{HCF}(42,53)} = 2226\)

Q141. Find the LCM of 26 and 46.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(26,46) = 598\) ... wait, let's compute:

\(\text{LCM}(26,46) = \frac{26 \times 46}{\text{HCF}(26,46)} = 598\)

Q142. Find the LCM of 58 and 49.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(58,49) = 2842\) ... wait, let's compute:

\(\text{LCM}(58,49) = \frac{58 \times 49}{\text{HCF}(58,49)} = 2842\)

Q143. Find the LCM of 6 and 53.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(6,53) = 318\) ... wait, let's compute:

\(\text{LCM}(6,53) = \frac{6 \times 53}{\text{HCF}(6,53)} = 318\)

Q144. Find the LCM of 37 and 12.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(37,12) = 444\) ... wait, let's compute:

\(\text{LCM}(37,12) = \frac{37 \times 12}{\text{HCF}(37,12)} = 444\)

Q145. Find the LCM of 29 and 6.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(29,6) = 174\) ... wait, let's compute:

\(\text{LCM}(29,6) = \frac{29 \times 6}{\text{HCF}(29,6)} = 174\)

Q146. Find the LCM of 60 and 48.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(60,48) = 240\) ... wait, let's compute:

\(\text{LCM}(60,48) = \frac{60 \times 48}{\text{HCF}(60,48)} = 240\)

Q147. Find the LCM of 29 and 33.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(29,33) = 957\) ... wait, let's compute:

\(\text{LCM}(29,33) = \frac{29 \times 33}{\text{HCF}(29,33)} = 957\)

Q148. Find the LCM of 19 and 33.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(19,33) = 627\) ... wait, let's compute:

\(\text{LCM}(19,33) = \frac{19 \times 33}{\text{HCF}(19,33)} = 627\)

Q149. Find the LCM of 18 and 47.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(18,47) = 846\) ... wait, let's compute:

\(\text{LCM}(18,47) = \frac{18 \times 47}{\text{HCF}(18,47)} = 846\)

Q150. Find the LCM of 52 and 33.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(52,33) = 1716\) ... wait, let's compute:

\(\text{LCM}(52,33) = \frac{52 \times 33}{\text{HCF}(52,33)} = 1716\)

Q151. Find the LCM of 9 and 58.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(9,58) = 522\) ... wait, let's compute:

\(\text{LCM}(9,58) = \frac{9 \times 58}{\text{HCF}(9,58)} = 522\)

Q152. Find the LCM of 22 and 33.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(22,33) = 66\) ... wait, let's compute:

\(\text{LCM}(22,33) = \frac{22 \times 33}{\text{HCF}(22,33)} = 66\)

Q153. Find the LCM of 35 and 29.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(35,29) = 1015\) ... wait, let's compute:

\(\text{LCM}(35,29) = \frac{35 \times 29}{\text{HCF}(35,29)} = 1015\)

Q154. Find the LCM of 34 and 42.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(34,42) = 714\) ... wait, let's compute:

\(\text{LCM}(34,42) = \frac{34 \times 42}{\text{HCF}(34,42)} = 714\)

Q155. Find the LCM of 10 and 24.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(10,24) = 120\) ... wait, let's compute:

\(\text{LCM}(10,24) = \frac{10 \times 24}{\text{HCF}(10,24)} = 120\)

Q156. Find the LCM of 57 and 25.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(57,25) = 1425\) ... wait, let's compute:

\(\text{LCM}(57,25) = \frac{57 \times 25}{\text{HCF}(57,25)} = 1425\)

Q157. Find the LCM of 18 and 17.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(18,17) = 306\) ... wait, let's compute:

\(\text{LCM}(18,17) = \frac{18 \times 17}{\text{HCF}(18,17)} = 306\)

Q158. Find the LCM of 7 and 32.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(7,32) = 224\) ... wait, let's compute:

\(\text{LCM}(7,32) = \frac{7 \times 32}{\text{HCF}(7,32)} = 224\)

Q159. Find the LCM of 37 and 27.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(37,27) = 999\) ... wait, let's compute:

\(\text{LCM}(37,27) = \frac{37 \times 27}{\text{HCF}(37,27)} = 999\)

Q160. Find the LCM of 29 and 25.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(29,25) = 725\) ... wait, let's compute:

\(\text{LCM}(29,25) = \frac{29 \times 25}{\text{HCF}(29,25)} = 725\)

Q161. Find the LCM of 29 and 23.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(29,23) = 667\) ... wait, let's compute:

\(\text{LCM}(29,23) = \frac{29 \times 23}{\text{HCF}(29,23)} = 667\)

Q162. Find the LCM of 46 and 54.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(46,54) = 1242\) ... wait, let's compute:

\(\text{LCM}(46,54) = \frac{46 \times 54}{\text{HCF}(46,54)} = 1242\)

Q163. Find the LCM of 26 and 7.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(26,7) = 182\) ... wait, let's compute:

\(\text{LCM}(26,7) = \frac{26 \times 7}{\text{HCF}(26,7)} = 182\)

Q164. Find the LCM of 32 and 32.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(32,32) = 32\) ... wait, let's compute:

\(\text{LCM}(32,32) = \frac{32 \times 32}{\text{HCF}(32,32)} = 32\)

Q165. Find the LCM of 50 and 7.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(50,7) = 350\) ... wait, let's compute:

\(\text{LCM}(50,7) = \frac{50 \times 7}{\text{HCF}(50,7)} = 350\)

Q166. Find the LCM of 23 and 44.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(23,44) = 1012\) ... wait, let's compute:

\(\text{LCM}(23,44) = \frac{23 \times 44}{\text{HCF}(23,44)} = 1012\)

Q167. Find the LCM of 20 and 31.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(20,31) = 620\) ... wait, let's compute:

\(\text{LCM}(20,31) = \frac{20 \times 31}{\text{HCF}(20,31)} = 620\)

Q168. Find the LCM of 48 and 56.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(48,56) = 336\) ... wait, let's compute:

\(\text{LCM}(48,56) = \frac{48 \times 56}{\text{HCF}(48,56)} = 336\)

Q169. Find the LCM of 9 and 19.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(9,19) = 171\) ... wait, let's compute:

\(\text{LCM}(9,19) = \frac{9 \times 19}{\text{HCF}(9,19)} = 171\)

Q170. Find the LCM of 45 and 8.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(45,8) = 360\) ... wait, let's compute:

\(\text{LCM}(45,8) = \frac{45 \times 8}{\text{HCF}(45,8)} = 360\)

Q171. Find the LCM of 31 and 57.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(31,57) = 1767\) ... wait, let's compute:

\(\text{LCM}(31,57) = \frac{31 \times 57}{\text{HCF}(31,57)} = 1767\)

Q172. Find the LCM of 29 and 19.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(29,19) = 551\) ... wait, let's compute:

\(\text{LCM}(29,19) = \frac{29 \times 19}{\text{HCF}(29,19)} = 551\)

Q173. Find the LCM of 6 and 7.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(6,7) = 42\) ... wait, let's compute:

\(\text{LCM}(6,7) = \frac{6 \times 7}{\text{HCF}(6,7)} = 42\)

Q174. Find the LCM of 24 and 30.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(24,30) = 120\) ... wait, let's compute:

\(\text{LCM}(24,30) = \frac{24 \times 30}{\text{HCF}(24,30)} = 120\)

Q175. Find the LCM of 45 and 36.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(45,36) = 180\) ... wait, let's compute:

\(\text{LCM}(45,36) = \frac{45 \times 36}{\text{HCF}(45,36)} = 180\)

Q176. Find the LCM of 14 and 27.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(14,27) = 378\) ... wait, let's compute:

\(\text{LCM}(14,27) = \frac{14 \times 27}{\text{HCF}(14,27)} = 378\)

Q177. Find the LCM of 20 and 41.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(20,41) = 820\) ... wait, let's compute:

\(\text{LCM}(20,41) = \frac{20 \times 41}{\text{HCF}(20,41)} = 820\)

Q178. Find the LCM of 20 and 48.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(20,48) = 240\) ... wait, let's compute:

\(\text{LCM}(20,48) = \frac{20 \times 48}{\text{HCF}(20,48)} = 240\)

Q179. Find the LCM of 19 and 36.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(19,36) = 684\) ... wait, let's compute:

\(\text{LCM}(19,36) = \frac{19 \times 36}{\text{HCF}(19,36)} = 684\)

Q180. Find the LCM of 9 and 57.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(9,57) = 171\) ... wait, let's compute:

\(\text{LCM}(9,57) = \frac{9 \times 57}{\text{HCF}(9,57)} = 171\)

Q181. Find the LCM of 52 and 17.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(52,17) = 884\) ... wait, let's compute:

\(\text{LCM}(52,17) = \frac{52 \times 17}{\text{HCF}(52,17)} = 884\)

Q182. Find the LCM of 60 and 21.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(60,21) = 420\) ... wait, let's compute:

\(\text{LCM}(60,21) = \frac{60 \times 21}{\text{HCF}(60,21)} = 420\)

Q183. Find the LCM of 31 and 13.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(31,13) = 403\) ... wait, let's compute:

\(\text{LCM}(31,13) = \frac{31 \times 13}{\text{HCF}(31,13)} = 403\)

Q184. Find the LCM of 28 and 38.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(28,38) = 532\) ... wait, let's compute:

\(\text{LCM}(28,38) = \frac{28 \times 38}{\text{HCF}(28,38)} = 532\)

Q185. Find the LCM of 53 and 44.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(53,44) = 2332\) ... wait, let's compute:

\(\text{LCM}(53,44) = \frac{53 \times 44}{\text{HCF}(53,44)} = 2332\)

Q186. Find the LCM of 39 and 43.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(39,43) = 1677\) ... wait, let's compute:

\(\text{LCM}(39,43) = \frac{39 \times 43}{\text{HCF}(39,43)} = 1677\)

Q187. Find the LCM of 55 and 55.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(55,55) = 55\) ... wait, let's compute:

\(\text{LCM}(55,55) = \frac{55 \times 55}{\text{HCF}(55,55)} = 55\)

Q188. Find the LCM of 55 and 45.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(55,45) = 495\) ... wait, let's compute:

\(\text{LCM}(55,45) = \frac{55 \times 45}{\text{HCF}(55,45)} = 495\)

Q189. Find the LCM of 14 and 38.

Difficulty: Easy-Medium · Topic: LCM of two numbers

Solution

We know \(\text{LCM}(a,b) = \frac{a \times b}{\text{HCF}(a,b)}\)

\(\text{HCF}(14,38) = 266\) ... wait, let's compute:

\(\text{LCM}(14,38) = \frac{14 \times 38}{\text{HCF}(14,38)} = 266\)

Q190. Find the largest number that divides 245 and 1029, leaving remainder 5 in each case.

Difficulty: Medium · Topic: Fundamental Theorem of Arithmetic

Solution

Required number divides (245−5)=240 and (1029−5)=1024.

240 = 2⁴×3×5; 1024 = 2¹⁰

HCF = 2⁴ = 16

Q191. Prove that √5 is irrational.

Difficulty: Medium · Topic: Irrational Numbers

Solution

Assume √5 = a/b (co-prime). Then a² = 5b², so 5|a, let a = 5k. Then 25k² = 5b² → b² = 5k², so 5|b. Both divisible by 5 contradicts co-primality. Hence √5 is irrational.

Q192. Prove that 3 + 2√5 is irrational.

Difficulty: Medium · Topic: Irrational Numbers

Solution

Assume 3 + 2√5 = a/b (rational). Then √5 = (a−3b)/(2b), which is rational — contradicts the irrationality of √5. Hence 3 + 2√5 is irrational.

Q193. HCF and LCM of two numbers are 9 and 360. If one number is 45, the other is:

Difficulty: Medium · Topic: Fundamental Theorem of Arithmetic

Solution

9 × 360 = 45 × x → x = 3240/45 = 72

Q194. Find the smallest number divisible by 15, 20 and 36 that leaves remainder 5 in each case.

Difficulty: Medium · Topic: Fundamental Theorem of Arithmetic

Solution

LCM(15,20,36) = 2²×3²×5 = 180. Required = 180 + 5 = 185

Q195. Show that any positive odd integer is of the form 6q+1, 6q+3, or 6q+5.

Difficulty: Medium · Topic: Euclid's Division Algorithm

Solution

a = 6q+r, r ∈ {0,1,2,3,4,5}. Even values: 6q, 6q+2, 6q+4. So odd integers: 6q+1, 6q+3, 6q+5.

Q196. 6ⁿ (n natural) can never end with digit:

Difficulty: Medium-Hard · Topic: Fundamental Theorem of Arithmetic

Solution

6ⁿ = 2ⁿ×3ⁿ has no factor 5, so never divisible by 10. Cannot end in 0. (In fact 6ⁿ always ends in 6.)

Q197. Three bells ring at intervals of 9, 12, and 15 minutes. If they ring together at 8 AM, when do they next ring together?

Difficulty: Medium-Hard · Topic: Fundamental Theorem of Arithmetic

Solution

LCM(9,12,15) = 2²×3²×5 = 180 min = 3 hours. Next: 8 AM + 3 h = 11:00 AM.

Q198. Prove that √2 + √3 is irrational.

Difficulty: Medium-Hard · Topic: Irrational Numbers

Solution

Assume √2+√3 = r (rational). Then √3 = r−√2. Square: 3 = r²−2r√2+2 → √2 = (r²−1)/(2r), rational — contradiction. Hence irrational.

Q199. Show that the square of any positive integer is of the form 3m or 3m+1.

Difficulty: Hard · Topic: Euclid's Division Algorithm

Solution

a = 3q → a² = 9q² = 3(3q²) = 3m.

a = 3q+1 → a² = 9q²+6q+1 = 3(3q²+2q)+1 = 3m+1.

a = 3q+2 → a² = 9q²+12q+4 = 3(3q²+4q+1)+1 = 3m+1.

Other Chapters in Mathematics

Ch 2: PolynomialsCh 3: Pair of Linear Equations in Two VariablesCh 4: Quadratic EquationsCh 5: Arithmetic ProgressionsCh 6: TrianglesCh 7: Coordinate GeometryCh 8: Introduction to TrigonometryCh 9: Some Applications of TrigonometryCh 10: CirclesCh 11: Areas Related to CirclesCh 12: Surface Areas and VolumesCh 13: StatisticsCh 14: Probability

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