$A$ pipe can fill a tank in $10 \, h$, while another pipe can empty it in $6 \, h$. Find the time (in $hours$) taken to empty the tank when both the pipes are opened simultaneously.

$A$ tap can fill an empty tank in $12$ $hours$ and another tap can empty the half-filled tank in $10$ $hours$. If both the taps are opened together,then how much time (in $hours$) will it take to fill an empty tank half-filled?

$A$ cistern can be filled by two pipes $A$ and $B$ in $4$ $hours$ and $6$ $hours$ respectively. When full,the tank can be emptied by a third pipe in $8$ $hours$. If all the taps are turned on at the same time,the cistern will be full in?

Taps $A, B$ and $C$ are attached to a tank. The rates of water flow through them are $42 \ L/h$,$56 \ L/h$,and $48 \ L/h$ respectively. $A$ and $B$ are inlet taps,while $C$ is an outlet tap. If all the taps are opened simultaneously,the tank is filled in $16 \ h$. What is the capacity of the tank (in $L$)?

$A$ cylindrical tank of diameter $25 \ cm$ is full of water. If $11 \ litres$ of water is drawn off,the water level in the tank will drop by (Use $\pi = 22/7$)?

One tap can fill a cistern in $2$ $hours$ and another can empty the cistern in $3$ $hours.$ How long will they take to fill the cistern if both the taps are opened?