A pipe can fill a tank in 'x' hours and another pipe can empty it in'y' (y > x) hours. If both the pipes are open , in how many hours will the tank be filled ?1). (x-y) hours2). (y-x) hours3). $\frac{xy}{x-y}$ hours4). $\frac{xy}{y-x}$ hours

A pipe can fill a tank in 'x' hours and another pipe can empty it in'y

1.	A pipe can fill a tank in 'x' hours and another pipe can empty it in'y' (y > x) hours. If both the pipes are open , in how many hours will the tank be filled ?1). (x-y) hours2). (y-x) hours3). $\frac{xy}{x-y}$ hours4). $\frac{xy}{y-x}$ hours
Answer» i THINK OPTION 4 is CORRECT