Two taps $A$ and $B$ can fill a tank in $10$ $hours$ and $15$ $hours$,respectively. If both the taps are opened together,the tank will be full in (in $hours$):

$A$ pipe can fill a tank with water in $5$ $hours$ and another pipe can empty the same tank in $4$ $hours$. If the tank is completely filled and both the taps are opened together,in how much time $(hours)$ will the tank be empty?

Three pipes $A, B$ and $C$ can fill a cistern in $6$ $hrs$. After working together for $2$ $hrs$,$C$ is closed and $A$ and $B$ fill the remaining part of the cistern in $8$ $hrs$. Find the time (in $hrs$) in which the cistern can be filled by pipe $C$ alone.

Three pipes $A, B$ and $C$ can fill a tank in $6$ $hours$. After working together for $2$ $hours$,$C$ is closed and $A$ and $B$ fill the remaining part in $7$ $hours$. The number of $hours$ taken by $C$ alone to fill the tank is?

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?

$A$ 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 $hours$)?