A pump can fill a cistern in 40 minutes and another pump can empty the filled up cistern in 1 hour. By mistake, without closing the second pump, the first pump is opened. The time in which the empty cistern will be filled up is

Water flows in to a tank 15 m.×10 m. through a rectangular pipe 2 m.×1.5 m. at 20 km./hr. In how much time will the water level in the tank rise by 3m.?

The pipe can fill a tank in 36 minutes and the another pipe can empty it in 45 minutes. If both pipes are opened simultaneously, the time (in hours) it takes to fill half the capacity of the tank is:

 Pipe A alone & pipe B alone can fill the same tank in 5 hours and 4 hours respectively. If the ratio of efficiency of pipe A & B together to that of pipe C alone is 9:2, then find time taken by pipe C alone to fill the same tank?

If 20 taps can fill a tank in 14 hours, then how many times will 35 taps fill that tank?

Two pipes, D and E, can fill a cistern in 26 and 78 hours, respectively, while working alone. If the two pipes are opened together, the time taken to fill the cistern is:

A Cistern can be filled by a tap in 4 hours while it can be emptied by another tap in 9 hours. If both the taps are opened simultaneously then after how much time will the cistern get filled?

Two pipes A and B can fill a tank in 3 hours and 5 hours. Then, if all three are open, the tank is filled in 30 hours. Find in how many hours a third pipe will empty the tank?