Multiple choice general knowledge math & puzzles

A is 60% more efficient as B.If A can do a work in 15 hours in what time will B be able to do it?

  1. 20

  2. 18

  3. 24

  4. 28

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If A is 60% more efficient than B, then B takes 60% longer than A to complete the same work. A completes in 15 hours, so B takes 15 × 1.6 = 24 hours. Alternatively, efficiency ratio A:B = 160:100 = 8:5, so time ratio (inversely proportional) is 5:8, giving 15 × 8/5 = 24 hours.