$10$ buckets of water fill a tank when the capacity of each bucket is $12$ litres. How many buckets will be needed to fill the same tank,if the capacity of each bucket is $8$ litres?

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 $hours$):

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 $minutes$)

$A$ 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?

$A$ booster pump can be used for filling as well as for emptying a tank. The capacity of the tank is $2400 m^3$. The emptying capacity of the tank is $10 m^3/min$ higher than its filling capacity and the pump needs $8$ minutes less to empty the tank than it needs to fill it. What is the filling capacity of the pump?

Two pipes $A$ and $B$ can fill a cistern in $3$ $hours$ and $5$ $hours,$ respectively. Pipe $C$ can empty it in $2$ $hours.$ If all the three pipes are open,in how many $hours$ will the cistern be full?