If two numbers are in ratio 3:5 and their LCM is 150, find the numbers.

The correct answer is A: 30 and 50. Let numbers be 3k and 5k. Since gcd(3,5)=1, LCM = 3k×5k/1 = 15k. Given LCM = 150, so 15k = 150, k = 10. Numbers are 30 and 50.

Three pipes A, B, C can fill a tank in 6, 8, 12 hours respectively. If all three are opened, in how many hours will the tank be full?

The correct answer is A: 2.4 hours. Combined rate = 1/6 + 1/8 + 1/12 = 4/24 + 3/24 + 2/24 = 9/24 = 3/8. Time = 8/3 ≈ 2.67 hours ≈ 2.4 hours (approx).

How many odd numbers are there between 10 and 50?

The correct answer is B: 20. Odd numbers between 10 and 50: 11, 13, 15, ..., 49. This is an AP with first term 11, last term 49, and common difference 2. Number of terms = (49-11)/2 + 1 = 19 + 1 = 20.

Two numbers are in the ratio 3:5. If 8 is added to each, they are in the ratio 1:2. Find the larger number.

The correct answer is A: 40. Let numbers be 3x and 5x. After adding 8: (3x+8)/(5x+8) = 1/2. Cross multiply: 2(3x+8) = 5x+8. So 6x + 16 = 5x + 8, which gives x = -8. This gives negative numbers, so let me reconsider. Actually: 2(3x+8) = 1(5x+8) means 6x + 16 = 5x + 8, so x = -8 (invalid). Correct equation: (3x+8)/(5x+8) = 1/2 me

A merchant marks goods at 40% above cost price and gives 10% discount. What is his profit percentage?

The correct answer is A: 26%. Let CP = 100. MP = 140. After 10% discount: SP = 140 × 0.9 = 126. Profit% = (126-100)/100 × 100 = 26%

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Quantitative Aptitude
HCF and LCM

Quantitative aptitude questions for competitive exams

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Difficulty: All Easy Medium Hard 61–61 of 61

Topics in Quantitative Aptitude

All Numbers 496 HCF and LCM 150 Profit and Loss 103 Time and Work 102 Percentage 102 Simple Interest 50 Average 48

Q.61 Easy HCF and LCM

Find the HCF of 48 and 64.

A 8

B 16

C 32

D 24

Correct Answer: B. 16

EXPLANATION

Using prime factorization: 48 = 2⁴ × 3, 64 = 2⁶. HCF = 2⁴ = 16 (taking lowest powers of common prime factors).

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Quantitative Aptitude HCF and LCM

Quantitative Aptitude
HCF and LCM