Two pipes A and B can fill the tank in 40 and 60 minutes, respectively. Both the pipes are opened together. After how many minutes should the pipe B be turned off, so that the tank be fill in 30 minutes?

A tank can be filled by one pipe in 8 hours and emptied by another pipe in 12 hours. How long will it take to fill the tank if both pipes are opened together?

Two pipes A and B can fill a tank in 28 hours and 21 hours, respectively. If both the pipes are opened simultaneously, then the time taken (in hours) to fill the tank is:

Two pipes, P and Q, together can fill a tank in 5 hours. If pipe P alone can fill the tank in 10 hours, then how much time (in hours) will pipe Q alone take to fill the tank?

Pipes A and B can fill a tank in 12 hours and 18 hours, respectively. Pipe C is an emptying pipe. When all the three pipes are opened together for 8 hours, then 26/45 part of the tank is filled up. What part of the tank will be filled up by A and C together in 9 hours?

Pipe A can fill a tank in 13 hours, pipe B can fill the same tank in 26 hours and pipe C can fill the same tank in 17 hours. The time taken by them to fill the same tank if they operate together is:

A leaking tap drips at the rate of 150 mL per hour. Water wasted in a day will be

Pipes P and Q can fill a tank in 18 hours and 27 hours respectively. Pipe R is an emptying pipe. When the tank is empty, P and Q are opened together for 6 hours and then both are closed and R is opened. The tank is now emptied in 30 hours. In how many hours can P and R together fill half the tank?

Two pipes A and B can fill a tank in 18 and 24 minutes respectively. After both are opened together for 6 minutes, the rate of pipe A becomes half, and pipe B becomes double its original. In how many more minutes will the tank be full?

Pipe A can fill a tank in 15 hours, pipe B can fill the same tank in 27 hours and pipe C can fill the same tank in 10 hours. The time taken by them to fill the same tank if they operate together is::

A pipe can fill a water tank in 36 minutes, and another can fill it in 48 minutes, but a third pipe can empty it in 18 minutes. The first two pipes are kept open for 16 minutes at the beginning, and then the third pipe is also opened. How long does it take to empty the tank?