Two pipes P and Q can fill a cistern in 36 and 48 minutes respectively. Both pipes are opened together, after how many minutes should Q be turned off,so that the cistern be fill in 24 minutes?

A water reservoir has two inlets and one outlet. Through the inlet it can be filled in 3 hours and 3 hours 45 minutes respectively. It can be emptied completely in 1 hour by the outlet. If the two inlets are opened at 01 : 00 pm and 02 : 00 pm respectively and the outlet at 03 : 00 pm then it will be emptied at : 

A tap can fill a Tank in 16 hours. Due to a hole in its base it is filled in 24 hours, If tank is full then in how many hours it will be empty through the hole. 

Pipe A can fill a tank in 4 hours and pipe B can fill it in 6 hours. If they are opened on alternate hours and if pipe A is opened first then in how many hours, the tank shall be full? 

12 pumps working 6 hours a day can empty a completely filled reservoir in 15 days. How many such pumps working 9 hours a day will empty the same reservoir in 12 days?

A tank is fitted with two taps. The first tap can fill the tank completely in 45 minutes and the second tap can empty the full tank in one hour. If both the taps are opened alternately for one minute, then in how many hours the empty tank will be filled completely?

A tap can fill a Tank in 16 hours. Due to a hole in its base it I filled in 24 hours, If tank is full then in how many hours it will be empty through the hole.

Three pipes A , B and C takes 15, 24 and 36 minutes respectively to fill a tank. Pipe D can empty it in 1 hour. If all the four pipes are kept open then find the time taken to fill the tank.