An inlet pipe fills $\frac{1}{8}$ part of a tank in $1 \ h$. How much time (in $h$) will the pipe take to fill the empty tank?

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 $gallons$):

Two pipes $A$ and $B$ can fill a tank in $30$ $minutes$ and $45$ $minutes$ respectively. Pipe $C$ can empty the tank in $36$ $minutes$. Initially,pipes $A$ and $B$ are opened. After $12$ $minutes$,pipe $C$ is also opened. What is the total time (in $minutes$) required to fill the tank?

$2$ pipes $A$ and $B$ can fill a tank separately in $60$ $min$ and $70$ $min$ respectively. There is a third pipe attached to the bottom of the tank to empty it. The tank is filled in $60$ $min$ when all three pipes are opened. In how much time $(min)$ will the third pipe alone take to empty the tank?

$A$ water tank is two-fifth full. Pipe $A$ can fill a tank in $10$ minutes,and pipe $B$ can empty it in $6$ minutes. If both the pipes are opened,how long will it take to empty or fill the tank completely?

$A$ large tanker can be filled by two pipes $A$ and $B$ in $60$ $minutes$ and $40$ $minutes$ respectively. How many minutes will it take to fill the tanker from an empty state if pipe $B$ is used alone for half the time and pipes $A$ and $B$ are used together for the other half?