HCF & LCM

Ladakh Prison Department · Mathematics · 79 practice questions with answers and explanations: 36 Easy, 42 Medium, 1 Hard.

Sample questions

Sample Easy question 1

What is the LCM of 18, 24 and 8?

  1. 3456
  2. 144
  3. 90
  4. 72
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Answer: D. LCM(18, 24, 8) = 72.

Sample Easy question 2

What is the HCF of 10, 8 and 12?

  1. 3
  2. 120
  3. 4
  4. 2
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Answer: D. HCF(10, 8, 12) = 2.

Sample Easy question 3

What is the smallest positive number that is exactly divisible by 2, 3 and 9?

  1. 18
  2. 36
  3. 20
  4. 54
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Answer: A. It is LCM(2, 3, 9) = 18.

Sample Medium question 4

What is the smallest number which leaves a remainder of 3 when divided by 6 as well as by 5?

  1. 63
  2. 32
  3. 33
  4. 30
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Answer: C. The required number is LCM(6, 5) + 3 = 30 + 3 = 33.

Sample Medium question 5

What is the smallest number which leaves a remainder of 2 when divided by 12 as well as by 18?

  1. 74
  2. 218
  3. 36
  4. 38
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Answer: D. The required number is LCM(12, 18) + 2 = 36 + 2 = 38.

Sample Medium question 6

What is the smallest number which leaves a remainder of 3 when divided by 10 as well as by 14?

  1. 143
  2. 73
  3. 72
  4. 70
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Answer: B. The required number is LCM(10, 14) + 3 = 70 + 3 = 73.

Sample Hard question 7

Find the HCF of the fractions 2/3, 4/9 and 8/27.

  1. 4/9
  2. 2/27
  3. 8/27
  4. 2/3
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Answer: B. HCF of fractions = HCF of numerators ÷ LCM of denominators = HCF(2, 4, 8) ÷ LCM(3, 9, 27) = 2/27.

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