Home Subjects Quantitative Aptitude HCF and LCM

Quantitative Aptitude
HCF and LCM

Quantitative aptitude questions for competitive exams

61 Q 7 Topics Take Mock Test
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Difficulty: All Easy Medium Hard 41–50 of 61
Topics in Quantitative Aptitude
Q.41 Easy HCF and LCM
A man invests ₹50,000 at 12% per annum SI for 2 years. If he had invested at CI instead, what additional amount would he earn?
A ₹720
B ₹1,200
C ₹1,440
D ₹2,000
Correct Answer:  A. ₹720
EXPLANATION

SI = 50000×12×2/100 = ₹12,000. CI = 50000(1.12)² - 50000 = ₹12,720. Difference = ₹720.

Test
Q.42 Easy HCF and LCM
The HCF of two numbers is 15 and their LCM is 450. If one of the numbers is 90, what is the other number?
A 60
B 75
C 85
D 105
Correct Answer:  B. 75
EXPLANATION

Using HCF × LCM = Product of two numbers:

15 × 450 = 90 × Other number

6750 = 90 × Other number

Other number = 6750 ÷ 90 = 75

Verification: HCF(90, 75) = 15 ✓ and LCM(90, 75) = 450 ✓

Test
Q.43 Easy HCF and LCM
Two numbers have an HCF of 12. If one number is 60, find the other number such that their LCM is 180.
A 30
B 36
C 48
D 72
Correct Answer:  B. 36
EXPLANATION

Using the formula: HCF × LCM = Product of two numbers

12 × 180 = 60 × Other number

2160 = 60 × Other number

Other number = 2160 ÷ 60 = 36

Verification: HCF(60, 36) = 12 ✓ and LCM(60, 36) = 180 ✓

Test
Q.44 Easy HCF and LCM
The HCF of two numbers is 6. If their LCM is 60 and one number is 12, find the other number.
A 20
B 24
C 30
D 18
Correct Answer:  C. 30
EXPLANATION

Using HCF × LCM = Product: 6 × 60 = 12 × other. 360 = 12 × other.

Other = 360 ÷ 12 = 30.

Test
Q.45 Easy HCF and LCM
The product of HCF and LCM of two numbers is 360. If one number is 20, find the other.
A 12
B 18
C 24
D 15
Correct Answer:  B. 18
EXPLANATION

HCF × LCM = Product of numbers = 360. 360 = 20 × other number.

Other number = 360 ÷ 20 = 18.

Test
Q.46 Easy HCF and LCM
What is the HCF of 72 and 90?
A 6
B 18
C 12
D 9
Correct Answer:  B. 18
EXPLANATION

72 = 2³ × 3², 90 = 2 × 3² × 5.

Common factors: 2 and 3². HCF = 2 × 3² = 2 × 9 = 18.

Test
Q.47 Easy HCF and LCM
What is the LCM of 20, 30, and 40?
A 60
B 120
C 90
D 180
Correct Answer:  B. 120
EXPLANATION

20 = 2² × 5, 30 = 2 × 3 × 5, 40 = 2³ × 5. LCM = 2³ × 3 × 5 = 8 × 3 × 5 = 120.

Test
Q.48 Easy HCF and LCM
Find the HCF of 45, 60, and 75.
A 5
B 15
C 10
D 20
Correct Answer:  B. 15
EXPLANATION

45 = 3² × 5, 60 = 2² × 3 × 5, 75 = 3 × 5².

Common factors: 3 and 5. HCF = 3 × 5 = 15.

Test
Q.49 Easy HCF and LCM
If HCF of two numbers is 15 and their product is 2700, find their LCM.
A 180
B 270
C 150
D 200
Correct Answer:  A. 180
EXPLANATION

Using the formula: HCF × LCM = Product of two numbers. 15 × LCM = 2700, so LCM = 2700 ÷ 15 = 180.

Test
Q.50 Easy HCF and LCM
Find the HCF of 84 and 126 using the Euclidean algorithm.
A 18
B 42
C 21
D 14
Correct Answer:  B. 42
EXPLANATION

Using Euclidean algorithm: 126 = 84 × 1 + 42, then 84 = 42 × 2 + 0.

Therefore, HCF(84, 126) = 42.

Test
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