$A$ 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?

Two pipes can separately fill a tank in $20$ $hrs$ and $30$ $hrs$ respectively. Both the pipes are opened to fill the tank,but when the tank is $\frac{1}{3}$ full,a leak develops in the tank through which $\frac{1}{3}$ of the water supplied by both the pipes per hour leaks out. What is the total time (in $hrs$) taken to fill the tank?

One fill pipe $A$ is $3$ times faster than second fill pipe $B$ and takes $32$ minutes less than the fill pipe $B$. When will the cistern be full if both the pipes are opened together?

$A$ cistern has two pipes. One can fill it in $8 \, h$ and the other can empty it in $5 \, h$. In how many $hours$ will the cistern be emptied if both the pipes are opened together when $\frac{3}{4}$ of the cistern is already full of water?

Three pipes $A, B$ and $C$ can fill a tank in $30 \ min$,$20 \ min$ and $10 \ min$,respectively. When the tank is empty,all the three pipes are opened. If $A, B$ and $C$ discharge chemical solutions $P, Q$ and $R$ respectively,then the part of solution $R$ in the liquid in the tank after $3 \ min$ is

$A$ tank can be filled by pipe $A$ in $2$ $hours$ and pipe $B$ in $6$ $hours.$ At $10 \, am$ pipe $A$ was opened. At what time will the tank be filled if pipe $B$ is opened at $11 \, am$?