$A$ pipe can empty a cistern in $27$ $hours$. Find the time (in $hours$) in which $\frac{2}{3}$ part of the cistern will be emptied?

$A$ tank is filled in $5$ $hours$ by three pipes $A, B$ and $C$. The pipe $C$ is twice as fast as $B$ and $B$ is twice as fast as $A$. How much time (in $hours$) will pipe $A$ alone take to fill the tank?

Two pipes,$A$ and $B,$ can separately fill a cistern in $15$ $minutes$ and $18$ $minutes,$ respectively,while a third pipe $C$ can empty it in $6$ $minutes.$ Two pipes,$A$ and $B,$ are kept open for $6$ $minutes$ in the beginning and,then the third pipe is also opened. In what time (in $minutes$) will the cistern be emptied?

$A$ tap takes $36$ hours extra to fill a tank due to a leakage equivalent to half of its inflow. In how many hours can the inlet pipe alone fill the tank?

One tap can fill a cistern in $2$ $hours$ and another can empty the cistern in $3$ $hours.$ How long will they take to fill the cistern if both the taps are opened?

$18$ pumps can fill a reservoir of capacity $1440 \text{ kilo liter}$ in $5 \text{ hours}$. How many $\text{hours}$ are required to fill a reservoir of capacity $1920 \text{ kilo liter}$ by $8$ pumps?