A pipe can fill a tank in 8 hours. Another pipe can empty it in 12 hours. If both pipes are opened together, in how many hours will the tank be filled?

Using the net work formula, the inlet pipe fills 1/8 of the tank per hour while the outlet pipe empties 1/12 per hour. The net filling rate is 1/8 - 1/12 = 3/24 - 2/24 = 1/24 of the tank per hour. The total time required to fill the tank is the reciprocal of the net rate, which is 24 hrs.

• Thanks
• Wrong explanation