A can do a piece of work in 18 days. B can do this work in 24 days. A started the work alone. After how many days should B join him, so that the work is finished in 15 days?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 11 days.
A can do a piece of work in 18 days. B can do this work in 24 days.
A's work in 15 days = 15/18 = 5/6
Remaining work = 1 - 5/6 = 1/6
Remaining work done by B alone in = 1/6 × 24 = 4 days
So, B should join after = 15 - 4 = 11 days