Two pipes $A$ and $B$ can fill a tank in $24$ $minutes$ and $32$ $minutes$ respectively. If both the pipes are opened simultaneously,after how much time (in $minutes$) should $B$ be closed so that the tank is full in $18$ $minutes$?

$A$ 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?

One tap can fill a cistern in $2$ hours and another can empty the cistern in $3$ hours. How long will it take to fill the cistern if both the taps are opened (in $\text{hours}$)?

Two taps $A$ and $B$ can fill an oil tank in $15$ $min$ and $18$ $min$ respectively,while a third tap is used to empty the tank. The third tap is opened after $6$ $min$ of opening of taps $A$ and $B$. If the tank empties in $16 \frac{1}{2}$ $min$ after opening the third tap,then in how much time (in $min$) can the third tap empty the full tank?

$A$ tank can be filled by pipe $A$ in $2$ $h$ and pipe $B$ in $6$ $h$. At $10$ $am$ pipe $A$ was opened. At what time will the tank be filled if pipe $B$ is opened at $11$ $am$?

Two taps can separately fill a cistern in $10$ $minutes$ and $15$ $minutes$ respectively. When the waste pipe is open,they can together fill it in $18$ $minutes$. The waste pipe can empty the full cistern in: