Question

A and b together can complete a work in 4 days. If a alone complete it the same task in 12 days how many days will b take to complete the task if he works alone

Answer 1

A and B can complete work in 12 days

So A and B's 1 day work = 1/12

A alone can complete work in 15 days

So A's 1 day work = 1/15

B's 1 day work = 1/12-1/15

=(1/60)(5-4)

=(1/60)

A leaves 10 days before completion of work so work done by B alone in last 10 days.

= 10×(1/60) = 1/6

work done before that = 1-1/6 = 5/6

5/6 work done by A and B together in.

= (5/6) × 12 = 10 days

Hence, A and B work together for 10 days.