Home Subjects Quantitative Aptitude HCF and LCM

Quantitative Aptitude
HCF and LCM

Quantitative aptitude questions for competitive exams

151 Q 7 Topics Take Test
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Difficulty: All Easy Medium Hard 131–140 of 151
Topics in Quantitative Aptitude
Q.131 Medium HCF and LCM
If the HCF of two numbers is 18 and their LCM is 324, one number is 36. The other number is:
A 162
B 180
C 196
D 216
Correct Answer:  A. 162
EXPLANATION

HCF × LCM = Product of numbers. 18 × 324 = 36 × other.

Therefore, other = 5832 ÷ 36 = 162.

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Q.132 Medium HCF and LCM
What is the LCM of 16, 24, and 36?
A 72
B 108
C 144
D 216
Correct Answer:  C. 144
EXPLANATION

16 = 2⁴, 24 = 2³ × 3, 36 = 2² × 3². LCM = 2⁴ × 3² = 16 × 9 = 144.

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Q.133 Medium HCF and LCM
The HCF of 56, 84, and 140 is:
A 14
B 28
C 7
D 4
Correct Answer:  A. 14
EXPLANATION

56 = 2³ × 7, 84 = 2² × 3 × 7, 140 = 2² × 5 × 7.

Common prime factors: 2 × 7 = 14.

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Q.134 Medium HCF and LCM
Two numbers are in the ratio 4:5, and their HCF is 6. Find the larger number.
A 24
B 30
C 36
D 48
Correct Answer:  B. 30
EXPLANATION

Let numbers be 4k and 5k. HCF = k = 6.

Therefore, numbers are 24 and 30.

The larger number is 30.

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Q.135 Easy HCF and LCM
Find the smallest number that is divisible by 12, 15, and 20.
A 60
B 120
C 180
D 240
Correct Answer:  A. 60
EXPLANATION

12 = 2² × 3, 15 = 3 × 5, 20 = 2² × 5. LCM = 2² × 3 × 5 = 60.

This is the smallest number divisible by all three.

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Q.136 Easy HCF and LCM
The LCM of two co-prime numbers is 221. What is the product of the numbers?
A 110
B 221
C 442
D 221
Correct Answer:  B. 221
EXPLANATION

For co-prime numbers, HCF = 1.

Using HCF × LCM = Product: 1 × 221 = Product.

Therefore, product = 221.

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Q.137 Medium HCF and LCM
What is the HCF of 144 and 196?
A 4
B 8
C 12
D 16
Correct Answer:  A. 4
EXPLANATION

144 = 2⁴ × 3². 196 = 2² × 7².

Common prime factors: 2².

Therefore, HCF = 4.

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Q.138 Medium HCF and LCM
The HCF of two numbers is 15. If their LCM is 180, and one number is 45, find the other number.
A 45
B 60
C 75
D 90
Correct Answer:  B. 60
EXPLANATION

Using HCF × LCM = Product of two numbers: 15 × 180 = 45 × other number.

Therefore, other number = 2700 ÷ 45 = 60.

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Q.139 Easy HCF and LCM
Find the LCM of 20 and 30.
A 30
B 60
C 90
D 120
Correct Answer:  B. 60
EXPLANATION

20 = 2² × 5, 30 = 2 × 3 × 5. LCM = 2² × 3 × 5 = 4 × 3 × 5 = 60.

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Q.140 Easy HCF and LCM
What is the HCF of 18 and 27?
A 6
B 9
C 12
D 18
Correct Answer:  B. 9
EXPLANATION

Factors of 18: 1, 2, 3, 6, 9, 18.

Factors of 27: 1, 3, 9, 27.

Common factors: 1, 3, 9.

Highest common factor = 9.

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