$A$ tap having diameter $d$ can empty a tank in $40$ $min$. How long will another tap having diameter $2d$ take to empty the same tank (in $min$)?

$A$ water tank has two taps $A$ and $B$. Tap $A$ can fill it in $6$ hours,and tap $B$ can empty it in $5$ hours. If both taps are opened simultaneously,how much time (in hours) is required to empty the tank?

Pipe $A$ can fill a tank in $4$ $hours$ and pipe $B$ can fill it in $6$ $hours$. If they are opened on alternate hours and if pipe $A$ is opened first,then in how many hours will the tank be full?

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 $L$)?

$A$ 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?

An inlet pipe fills $\frac{1}{8}$ part of a tank in $1 \ h$. How much time (in $h$) will the pipe take to fill the empty tank?