$A$ tank can be filled with water by two pipes $A$ and $B$ together in $36$ minutes. If the pipe $B$ was closed after $30$ minutes,the tank is filled in $40$ minutes. The pipe $B$ can alone fill the tank in?

If two pipes function simultaneously,the reservoir will be filled in $6$ $hours$. One pipe fills the reservoir $5$ $hours$ faster than the other. How many hours does the faster pipe take to fill the reservoir?

$A$ 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 $hours$)?

Pipe $A$ can fill a cistern in $6 \, h$ and pipe $B$ can fill it in $8 \, h$. Both the pipes are opened simultaneously,but after $2 \, h$ pipe $A$ is closed. How many hours will $B$ take to fill the remaining part of the cistern?

$A, B$ and $C$ are three pipes connected to a tank. $A$ and $B$ together fill the tank in $6$ $hrs$. $B$ and $C$ together fill the tank in $10$ $hrs$,and $C$ and $A$ together fill the tank in $7 \frac{1}{2}$ $hrs$. In how much time (in $hours$) will $A, B$ and $C$ fill the tank together?

Two pipes can separately fill a tank in $20$ $hrs$ and $30$ $hrs$ respectively. Both the pipes are opened to fill the tank,but when the tank is $\frac{1}{3}$ full,a leak develops in the tank through which $\frac{1}{3}$ of the water supplied by both the pipes per hour leaks out. What is the total time (in $hrs$) taken to fill the tank?