The ratio of working efficiency of A and B is 4 : 5. If A alone completes the work in 15 days then in how many days can B alone complete the work?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 12 days
Time taken for the same work is inversely proportional to efficiency: the more efficient worker takes less time.
Efficiencies A : B \(=4:5\), so times A : B \(=5:4\)
A takes 15 days, so B takes \(15\times\frac{4}{5}=12\) days