Q) A can do a piece of work in 4 hours; B and C together can do it in 3 hours, while A and C together can do it in 2 hours.

How long will B alone take to do it?

a) 8 hours       b) 10 hours            c) 12 hours              d) 24 hours

Ans:

A’s 1 hr’s work = 1/4

(B + C)’s 1 hr work = 1/3

∴ (A + B + C)’s 1 hr work = 1/4 + 1/3 = 7/12

Given that (A + C)’s 1 hr work = 1/2

∴ B’s 1 hr work = 7/12 – 1/2 = 1/12

∴ Time taken by B alone to finish whole work = 12 hours

Hence, Answer is [C].

Please do press “Heart” button if you liked the solution.