Three pipes $A$,$B$,and $C$ can fill a cistern in $10$,$12$,and $15$ $hours$,respectively,while working alone. If all the three pipes are opened together,the time taken to fill the cistern will be:

$A$ pipe fills a water tank three times faster than another pipe. If the two pipes together can fill the empty tank in $36$ $minutes$,then how much time will the slower pipe alone take to fill the tank?

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?

Two pipes can fill a tank in $20$ and $24$ $minutes$ respectively and a waste pipe can empty $3$ $gallons$ per $minute$. All the three pipes working together can fill the tank in $15$ $minutes$. The capacity of the tank is?

If a pipe fills a tank in $6 \ h$,then what part of the tank will the pipe fill in $1 \ h$?

$A$ tap can fill a tank in $25$ $minutes$ and another can empty it in $50$ $minutes$. Find out whether the tank will be filled up or emptied and in how many $minutes$?