Quantitative Aptitude • Number System & SimplificationEasy
What is the HCF (highest common factor) of 25 and 15?
A. 15
B. 5✓ Correct Answer
C. 75
D. 10
💡 Solution & Explanation
Write both numbers using a common factor: 25 = 5 × 5 and 15 = 5 × 3. The numbers 5 and 3 have no common factor other than 1, so nothing larger than 5 divides both. Therefore the HCF of 25 and 15 is 5. A quick check: the HCF must also divide the difference of the two numbers, and 10 ÷ 5 = 2.
More Quantitative Aptitude Number System & Simplification questions
- What is the HCF (highest common factor) of 143 and 91?
- A number leaves a remainder of 39 when divided by 49. What remainder will it leave when divided by 7?
- What is the smallest number that must be added to 7,795 so that the result is exactly divisible by 7?
- Simplify: (18² − 13²) ÷ (18 − 13)
- What is the greatest number that divides 414, 339 and 377, leaving remainders 6, 16 and 3 respectively?