Question

A and b can do a work in 5 days. a alone can do the same work in 8 days. in how many days will b do the same work?

Answer 1

8 days b Will do his work

Answer 2

(A + B)’s 1 day’s work =\frac{1}{5}

A’s 1 day’s work =\frac{1}{8}

∴ B’s 1 day’s work =\frac{1}{5}-\frac{1}{8}=\frac{8-5}{40}=\frac{3}{40}

∴ B alone will complete the work in \frac{40}{3}=13\tfrac{1}{3}\ days.

Hence option [B] is correct answer.