Quantitative Aptitude — MCQ Practice Questions & Answers

Question 1

Find the HCF and LCM of 36 and 48. What is their product?

Accepted Answer

Correct answer: A. 1728 — 36 = 2² × 3², 48 = 2⁴ × 3. HCF = 2² × 3 = 12, LCM = 2⁴ × 3² = 144. Product = 36 × 48 = HCF × LCM = 12 × 144 = 1728.

Answer

B. 1440

Answer

C. 1296

Answer

D. 1680

Question 2

Two numbers have HCF of 8 and LCM of 96. If one number is 24, find the other number.

Accepted Answer

Correct answer: A. 32 — Using formula: HCF × LCM = Product of two numbers. 8 × 96 = 24 × x. 768 = 24x. x = 32.

Answer

B. 40

Answer

C. 48

Answer

D. 64

Question 3

What is the HCF of 100, 150, and 200?

Accepted Answer

Correct answer: B. 50 — 100 = 2² × 5², 150 = 2 × 3 × 5², 200 = 2³ × 5². Common factors: 2¹ × 5² = 2 × 25 = 50.

Answer

A. 25

Answer

C. 75

Answer

D. 100

Question 4

Find the LCM of 84 and 140.

Accepted Answer

Correct answer: A. 420 — This question asks us to find the least common multiple (LCM) of two numbers using prime factorization. Step 1: Find prime factorization of 84 Break 84 into its prime factors by dividing by smallest primes. 84 = 2^2 	imes 3 	imes 7 Step 2: Find prime factorization of 140 Break 140 into its prime factors by dividing by smallest primes. 140 = 2^2 	imes 5 	imes 7 Step 3: Calculate LCM using highest powers of all prime factors LCM is found by taking the highest power of each prime factor that appears in either number. 	ext{LCM} = 2^2 	imes 3 	imes 5 	imes 7 = 4 	imes 3 	imes 5 	imes 7 = 420 The LCM of 84 and 140 is 420, which is option (A).

Answer

B. 840

Answer

C. 210

Answer

D. 280

Question 5

The HCF of two numbers is 15. If their LCM is 180, and one number is 45, find the other number.

Accepted Answer

Correct answer: B. 60 — Using HCF × LCM = Product of two numbers: 15 × 180 = 45 × other number. Therefore, other number = 2700 ÷ 45 = 60.

Answer

A. 45

Answer

C. 75

Answer

D. 90

Question 6

What is the HCF of 144 and 196?

Accepted Answer

Correct answer: A. 4 — 144 = 2⁴ × 3². 196 = 2² × 7². Common prime factors: 2². Therefore, HCF = 4.

Answer

B. 8

Answer

C. 12

Answer

D. 16

Question 7

Two numbers are in the ratio 4:5, and their HCF is 6. Find the larger number.

Accepted Answer

Correct answer: B. 30 — Let numbers be 4k and 5k. HCF = k = 6. Therefore, numbers are 24 and 30. The larger number is 30.

Answer

A. 24

Answer

C. 36

Answer

D. 48

Question 8

The HCF of 56, 84, and 140 is:

Accepted Answer

Correct answer: A. 14 — 56 = 2³ × 7, 84 = 2² × 3 × 7, 140 = 2² × 5 × 7. Common prime factors: 2 × 7 = 14.

Answer

B. 28

Answer

C. 7

Answer

D. 4

Quantitative Aptitude - MCQ Practice Questions