Quantitative Aptitude — MCQ Practice Questions & Answers

Question 1

What is the sum of the first 10 natural numbers?

Accepted Answer

Correct answer: B. 55 — Sum of first n natural numbers = n(n+1)/2. Here n=10, so sum = 10(11)/2 = 110/2 = 55

Answer

A. 45

Answer

C. 50

Answer

D. 60

Question 2

Find the smallest prime number greater than 20.

Accepted Answer

Correct answer: B. 23 — Check: 21=3×7 (not prime), 23 is only divisible by 1 and 23 (prime), 25=5×5 (not prime), 27=3×9 (not prime). So 23 is the smallest prime greater than 20.

Answer

A. 21

Answer

C. 25

Answer

D. 27

Question 3

What is the HCF (Highest Common Factor) of 48 and 64?

Accepted Answer

Correct answer: C. 16 — Factors of 48: 1,2,3,4,6,8,12,16,24,48. Factors of 64: 1,2,4,8,16,32,64. Common factors: 1,2,4,8,16. HCF = 16

Answer

A. 8

Answer

B. 12

Answer

D. 24

Question 4

If a number is divisible by both 3 and 5, by which of these is it always divisible?

Accepted Answer

Correct answer: B. 15 — If a number is divisible by both 3 and 5, and 3 and 5 are coprime (HCF=1), then the number must be divisible by their product: 3×5 = 15

Answer

A. 8

Answer

C. 20

Answer

D. 25

Question 5

What is the product of the first five prime numbers?

Accepted Answer

Correct answer: A. 2310 — First five prime numbers are 2, 3, 5, 7, 11. Product = 2 × 3 × 5 × 7 × 11 = 2310

Answer

B. 2520

Answer

C. 2100

Answer

D. 2640

Question 6

Which of the following is a perfect square?

Accepted Answer

Correct answer: B. 169 — This question asks us to identify which number is a perfect square (a number that equals an integer multiplied by itself). Step 1: Understand Perfect Squares A perfect square is a number that can be expressed as n × n where n is an integer. 	ext{Perfect Square} = n^2 Step 2: Check Each Option Test each option by finding if its square root is a whole number. \sqrt{145} \approx 12.04, \quad \sqrt{169} = 13, \quad \sqrt{200} \approx 14.14, \quad \sqrt{198} \approx 14.07 Step 3: Verify the Correct Answer Only 169 has a whole number square root. 13 	imes 13 = 169 169 is a perfect square because 13 × 13 = 169, making the correct answer (B).

Answer

A. 145

Answer

C. 200

Answer

D. 198

Question 7

What is the difference between the largest 3-digit number and the smallest 3-digit number?

Accepted Answer

Correct answer: A. 899 — Largest 3-digit number = 999, Smallest 3-digit number = 100. Difference = 999 - 100 = 899

Answer

B. 900

Answer

C. 899

Answer

D. 901

Question 8

If a number is multiplied by 8 and then 15 is subtracted, the result is 49. What is the number?

Accepted Answer

Correct answer: B. 8 — This question asks us to find an unknown number based on a sequence of arithmetic operations performed on it. Step 1: Set up the equation Let the unknown number be x. According to the problem, when x is multiplied by 8 and then 15 is subtracted, the result is 49. 8x - 15 = 49 Step 2: Isolate the variable term Add 15 to both sides of the equation to move the constant to the right side. 8x - 15 + 15 = 49 + 15 8x = 64 Step 3: Solve for the number Divide both sides by 8 to find the value of x. x = \frac{64}{8} = 8 The number is 8, which corresponds to answer choice (B).

Answer

A. 6

Answer

C. 9

Answer

D. 7

Quantitative Aptitude - MCQ Practice Questions