A pipe can fill a tank in x hours and another can empty it in y hours. They can together fill it in (y x)?

Question

A pipe can fill a tank in x hours and another can empty it in y hours. They can together fill it in (y > x)?

Accepted Answer

Net filling in 1 hour = (1/x - 1/y) = (y - x) / xy ∴ Time taken to fill the tank = xy / (y - x) hrs.

A pipe can fill a tank in x hours and another can empty it in y hours. They can together fill it in (y > x)?