A cistern can be filled by two pipes filling separately in 8 and 10 minutes respectively. Both the pipes are opened together but being clogged for a certain time, only $\frac{7}{10}$ of the full quantity of water flows through the former and only $\frac{3}{8}$ through the later pipe. The obstructions, however, being suddenly removed, the cistern is filled in 2 minutes from that moment. How long was it before the full flow began?

Two pipes A and B can fill a tank in 20 minutes and 10 minutes respectively. Both pipes A and B are opened together for some time and then pipe B is turned off. If the tank is filled in 15 minutes, then find after how many minutes pipe B is turned off?

A pipe can fill a tank in 6 hours. Due to a leak in its bottom, it is filled in 7 hours. If the tank is full, then the time it will take to empty it because of the leak is:

Two pipes can fill a tank in 12 and 15 minutes respectively and a waste pipe can empty 3.4 litres per minute. All the three pipes working together can fill the tank in 18 minutes. The capacity of the tank is

A pump can fill a tank with water in 2 hours. Because of a leak, it took $2\frac{1}{3}$ hours to fill the tank. In how many hours can the leak drain all the water from the tank?

Pipe A can fill the tank 3 times faster than pipe B. If both pipes A and B running together can fill the tank in 15 minutes, then the time taken by B alone to fill the tank is:

A pipe A can fill a tank in 4 hours. There are two outlet pipes, B and C, from the tank which can empty it in 8 and 10 hours respectively. If all the three pipes are opened simultaneously, how long will it take to fill the tank?