If A and B together can complete a piece of work in 15 days and B alone in 20 days, then in how many days can A alone complete the work ?
If A and B together can complete a piece of work in 15 days and B alone in 20 days, then in how many days can A alone complete the work ?
[A]30 days
[B]40 days
[C]45 days
[D]60 days
60 days
(A + B)’s 1 day’s work $latex = \frac{1}{15}&s=1$
B’s 1 day’s work $latex = \frac{1}{20}&s=1$
∴ A’s 1 day’s work $latex = \frac{1}{15}-\frac{1}{20} = \frac{4-3}{60}= \frac{1}{60}&s=1$
∴ A alone will do the work in 60 days.
Hence option [D] is correct answer.