Pipe 1 and 2 can fill a tank alone in 6 hours and 9 hours respectively. Pipe 3 can empty the full tank in 18 hours. If all the 3 pipes are opened simultaneously, then how much time is required to fill the tank completely?

Pipe A and B can fill a tank in 12 and 15 hours respectively. An outlet pipe C, can empty it in 6 hours. Initially pipes A and B are opened together, and after 5 hours pipe C is also opened. Find the time required to empty the tank?

Three pipes 1, 2 and 3 together take 24 hours to fill a tank. The three pipes are opened for 6 hours after which Pipe 3 is closed. Pipe 1 and 2 take another 30 hours to fill the tank. In how much time would Pipe 3, alone fill the tank?

Two pipes x and y can fill a tank in 24 and 30 minutes respectively. Both the pipes are opened for 6 minutes, after which Pipe x is turned off. How much more time will it take to fill the tank?

A tank is usually filled in 18 hours. But because of a leak in it’s bottom, it takes another 6 hours to fill. How much time will it take to the leak to empty the full tank?