$A$ pipe can fill a tank in $x$ $h$ and another pipe can empty it in $y$ $(y > x)$ $h.$ If both the pipes are open,in how many hours will the tank be filled?

An empty pool being filled with water at a constant rate takes $8$ $hours$ to fill $\frac{3}{5}$ of its capacity. How much more time will it take to finish filling the pool?

Two pipes can fill a cistern separately in $24$ $minutes$ and $40$ $minutes$ respectively. $A$ waste pipe can drain off $30 \text{ litres per minute}$. If all the three pipes are opened,the cistern fills in one $hour$. The capacity (in $litres$) of the cistern is:

There are two taps to fill a tank while a third tap is used to empty it. When the third tap is closed,the first two taps can fill the tank in $10$ $minutes$ and $12$ $minutes$ respectively. If all three taps are opened,the tank is filled in $15$ $minutes$. If the first two taps are closed,in what time can the third tap empty the tank when it is full?

Two pipes $A$ and $B$ can fill a tank in $37 \frac{1}{2}$ minutes and $45$ minutes respectively. If both pipes are opened together,after how much time (in minutes) should pipe $B$ be closed so that the tank is full in exactly $30$ minutes?

$A$ pump can fill a tank with water in $2$ $hours$. Because of a leak,it took $2 \frac{1}{3}$ $hours$ to fill the tank. The leak can drain all the water of the tank in (in $hours$)?