Question

A person X can do a piece of work in 20 days.He worked at it for 5 days and then Y finished it in 15 days. In how many days can X and Y can together finish the work.

Answer 1

work - done by x = done by y
20-5 =15
its mean that speed of both of them is same .
so if both of them work at the same time then the speed twice .So, the work will be done in 10 days