$A$ cistern has a leak which would empty it in $8$ $hours$. $A$ tap is turned on which admits $6$ $litres$ a minute into the cistern,and it is now emptied in $12$ $hours$. How many $litres$ does the cistern hold?

$A$ tank can be filled by one tap in $20$ $minutes$ and by another in $25$ $minutes$. Both the taps are kept open for $5$ $minutes$ and then the second is turned off. In how many $minutes$ more will the tank be completely filled?

$A$ cistern has two taps which fill it in $12$ $minutes$ and $15$ $minutes$ respectively. There is also a waste pipe in the cistern. When all the pipes are opened,the empty cistern is filled in $20$ $minutes$. How long will the waste pipe take to empty a full cistern?

Two pipes $A$ and $B$ can fill a tank in $20$ $minutes$ and $30$ $minutes$ respectively. If both the pipes are used together,then how long will it take to fill the tank? (in $minutes$)

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

$A$ cistern is filled by two taps $A$ and $B$. Tap $A$ can fill it in $20$ $minutes$ and tap $B$ in $25$ $minutes$. Both the taps are kept open for $5$ $minutes$ and then the second tap $(B)$ is turned off. The cistern will be completely filled in another: