Pipes and Cisterns

 Two pipes A and B can fill a tank in 20 minutes and 30 minutes respectively. If both the pipes are opened together, the time taken by them to half – full the cistern is

• 12 minutes

• 6 minutes

• 9 minutes

• 18 minutes

An outlet pipe can empty a cistern in 3 hours. The time taken by it to empty rd of the cistern is

• 2 minutes

• 3 minutes

• 4 minutes

• 6 minutes

• 7/2 hours

• 7/4 hours

• 4/3 hours

• 3/4 hours

A cistern has two taps which fill it in 12 minutes and 15 minutes respectively. There is also a waste pipe in the cistern. When all the three pipes are opened, the empty cistern is full in 20 minutes. How long will the waste pipe take to empty the full cistern?

• 10 minutes

• 8 minutes

• 20 minutes

• 5 minutes

A pipe can fill a tank in 3 hours. Because of a leak in the tank the pipe takes 3 hours 30 minutes to fill the tank. How much time will the leak take to empty the full tank?

• 7 hours

• 6 1/2 hours

• 1/2 hours

• 21 hours

There is a leak in the bottom of a cistern. Before the leak, it could be filled in 4½ hours. It now takes ½ hour longer. If the cistern is full, how long will the leakage take to empty the full cistern?

• 30 hours

• 5 hours

• 45 hours

• 15 hours

A pipe A can fill a tank in 25 minutes and pipe B can empty the full tank in 50 minutes. The time taken by two pipes to fill the tank is

• 20 minutes

• 25 minutes

• 30 minutes

• 10 minutes

• 16 minutes

• 15 minutes

• 8 minutes

• 10 minutes

A pipe can fill an empty cistern in 5 hours. A leak develops in the cistern due to which full cistern is emptied in 30 hours. With the leak, the cistern can be filled in

• 8 Hours

• 6 Hours

• 10 hours

• 12 Hours