Arithmetic Questions And Answers :: Pipes Cisterns: part1

11.A pipe can fill a tank in x hours and another can empty it in y hours. They can together fill it in (y>x):

12.A tank can be filled by one tap in 20 min, and by another in 25 min. both the taps are kept open for 5 min, and then the second is turned off. In how many minutes more is the tank completely filled?

13.A cistern has a leak which would empty it in 8 hours. A tap is turned on which admits 6 litres a minute into the cistern and it is now emptied in 12 hours. How many litres does the cistern hold?

14.A pipe can fill a cistern in 12 minutes and another pipe can full it in 15 minutes, but a third pipe can empty it in 6 minutes. The first two pipes are kept open for 5 minutes in the beginning and then the third pipe is also opened. In what time is the cistern emptied?

15.There are two taps to fill a tank while a third to empty it. When the third tap is closed, they can fill the tank in 10 minutes and 12 minutes respectively. If all the three taps be opened, the tank is filled in 15 minutes. If the first two taps are closed in what time can the third tap empty the tank when it is full?