LCM and HCF: Test 2

10 questions · 15 minutes · scoring and calculator rules shown before you begin

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LCM and HCF Test 2: questions and answers

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  1. 1. Find the LCM of 5, 10, 15.
    1. 750
    2. 5
    3. 35
    4. 30

    Reference: q-542f4f5e-27 · Report this question

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    Answer: D. 30

    LCM of 5, 10, 15 = 30, the smallest number divisible by all three.
  2. 2. Find the HCF of 18 and 30.
    1. 5
    2. 3
    3. 6
    4. 90

    Reference: q-894a5a36-27 · Report this question

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    Answer: C. 6

    18 = 6 × 3 and 30 = 6 × 5, where 3 and 5 have no common factor. HCF = 6.
  3. 3. The HCF and LCM of two numbers are 10 and 350. If one of the numbers is 50, find the other.
    1. 70
    2. 80
    3. 35
    4. 40

    Reference: q-384dbd1-92 · Report this question

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    Answer: A. 70

    Product of the numbers = HCF × LCM. Other number = 10 × 350 / 50 = 70.
  4. 4. Three bells ring at intervals of 6, 9 and 12 seconds. If they ring together now, after how many seconds will they next ring together?
    1. 30 seconds
    2. 27 seconds
    3. 18 seconds
    4. 36 seconds

    Reference: q-a3cc4ad0-134 · Report this question

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    Answer: D. 36 seconds

    They ring together again after the LCM of 6, 9, 12, which is 36 seconds.
  5. 5. Find the least number which when divided by 10, 15, 25 leaves a remainder of 2 in each case.
    1. 150
    2. 158
    3. 152
    4. 148

    Reference: q-2adf2399-93 · Report this question

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    Answer: C. 152

    LCM of 10, 15, 25 = 150. Required number = 150 + 2 = 152.
  6. 6. Find the greatest number that divides 17 and 37 leaving remainders 3 and 2 respectively.
    1. 8
    2. 7
    3. 4
    4. 10

    Reference: q-8a6b6f94-89 · Report this question

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    Answer: B. 7

    Required number = HCF of (17 − 3) and (37 − 2) = HCF of 14 and 35 = 7.
  7. 7. Find the LCM of 12, 15, 20.
    1. 60
    2. 1
    3. 30
    4. 3,600

    Reference: q-b7598853-28 · Report this question

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    Answer: A. 60

    LCM of 12, 15, 20 = 60, the smallest number divisible by all three.
  8. 8. Find the HCF of 55 and 88.
    1. 440
    2. 14
    3. 11
    4. 13

    Reference: q-f1fd3bec-27 · Report this question

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    Answer: C. 11

    55 = 11 × 5 and 88 = 11 × 8, where 5 and 8 have no common factor. HCF = 11.
  9. 9. The HCF and LCM of two numbers are 4 and 40. If one of the numbers is 20, find the other.
    1. 16
    2. 4
    3. 8
    4. 10

    Reference: q-4cfe2e9f-90 · Report this question

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    Answer: C. 8

    Product of the numbers = HCF × LCM. Other number = 4 × 40 / 20 = 8.
  10. 10. Three bells ring at intervals of 5, 10 and 15 seconds. If they ring together now, after how many seconds will they next ring together?
    1. 20 seconds
    2. 30 seconds
    3. 40 seconds
    4. 45 seconds

    Reference: q-d00362da-135 · Report this question

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    Answer: B. 30 seconds

    They ring together again after the LCM of 5, 10, 15, which is 30 seconds.

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