Quantitative Aptitude · Mathematics

HCF and LCM

215 Questions

Improve your quantitative aptitude speed by solving these HCF and LCM questions. The problems involve finding the highest common factor and least common multiple for sets of numbers. These calculations form a core part of the mathematics section in SSC, banking, and railway recruitment exams.

Finding HCFFinding LCMGreatest common factorLeast common multipleNumber properties

HCF and LCM Questions

Multiple choice

LCM of 18 and 7 is ______.

  1. 18

  2. 104

  3. 126

  4. 128
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Multiples of 18 = 18, 36, 54, 72, 90, 108, 126 Multiples of 7 = 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98, 105, 112, 119, 126 LCM of 18 and 7 = 126

Multiple choice

Find the LCM of 18 and 24?

  1. 24

  2. 36

  3. 48

  4. 72
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Multiples of 18 are 18, 36, 54, 72, 90. Multiples of 24 are 24, 48, 72, 96. So, 72 is the LCM of 18 and 24.

Multiple choice

Find the HCF of 36, 54 and 45.

  1. 8

  2. 9

  3. 10

  4. 11
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Factors of 36 are 1, 2, 4, 6, 9, 12, 18, and 36. Factors of 54 are 1, 2, 3, 6, 9, 18, 27, and 54. Factors of 45 are 1, 3, 5, 9, 15, and 45. So, 9 is the HCF.

Multiple choice

Find the LCM of 9 and 12.

  1. 27

  2. 36

  3. 48

  4. 108
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

LCM of 9 and 12  Multiples of 9 are 9, 18, 27, 36, 45, 54. Multiples of 12 are 12, 24, 36, 48. 36 is the LCM.

Multiple choice

What is the greatest common factor of 84 and 56?

  1. 14

  2. 28

  3. 29

  4. 32
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Greatest common factor of 84 and 56 is 28. Factors of 84 are 1, 2, 3, 4, 6, 7, 12, 14, 21, 28 and 42. Factors of 28 are 1, 2, 4, 7, 14, 28. So, greatest number which is common is 28.

Multiple choice

If the greatest common factor (GCF) of two numbers is one of those numbers then their least common multiple(LCM) shall be

  1. The smaller of the two numbers

  2. The product of the two numbers

  3. The larger of the two numbers

  4. The difference of the two numbers

  5. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If the Greatest Common Factor (GCF) of two numbers is one of those numbers then their Least Common Multiple(LCM) shall be the larger of the two numbers.

For e.g. if the two numbers are 4 & 8 then HCF or GCF is 4 but LCM shall be 8.