Pipes and Cisterns

One-fourth of a tank holds135 litres of water. What part of the tank is full if contains 180 litres of water?

A tank can be filled by A in 60 minutes and emptied by B in 75 minutes. The tank is half filled and Ravi wants to fill the tank but opens B mistakenly and realizes after half hour and closed tap B. He then opens A and tank is completely filled in _______ minutes.

Pipes A and B can fill a tank in 12 minutes and 15 minutes, respectively. The tank when full can be emptied by pipe C in x minutes. When all the three pipes are opened simultaneously, the tank is full in 10 minutes. The value of x is:

Pipes A and B can fill a tank in 43.2 minutes and 108 minutes, respectively. Pipe C can empty it at 3 litres/minute. When all the three pipes are opened together, they fill the tank in 54 minutes. The capacity (in litres) of the tank is:

There are two inlets A and B connected to a tank. A and B can fill the tank in 32 h and 28 h, respectively. If both the pipes are opened alternately for 1 h, starting with A, then in how much time (in hours, to nearest integer) will the tank be filled?