Two pipes can fill a tank in $20$ $minutes$ 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 (in $gallons$):

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

If two pipes function simultaneously,the reservoir will be filled in $12$ $hours$. One pipe fills the reservoir $10$ $hours$ faster than the other. How many $hours$ does the faster pipe take to fill the reservoir?

An outlet pipe can empty a cistern in $3$ $h$. In what time (in $h$) will the pipe empty two-third part of the cistern?

Two pipes $A$ and $B$ can fill a cistern in $20$ $minutes$ and $25$ $minutes$ respectively. Both are opened together,but after $5$ $minutes,$ $B$ is turned off. How much time (in $minutes$) longer will the cistern take to fill?

$A$ cistern has $3$ pipes $A, B$ and $C$. Pipes $A$ and $B$ can fill it in $3$ and $4$ hours respectively,and pipe $C$ can empty it in $1$ hour. If the pipes are opened at $3 \text{ pm}$,$4 \text{ pm}$,and $5 \text{ pm}$ respectively on the same day,at what time will the cistern be empty?