At a dairy plant, a milk tank can be filled in 6 hours (using the in-valve). Using the out-valve, the tank can be emptied in 15 hours. If both valves are open and milk is being pumped into the tank, how long will it take to fill the tank?
1 Answer
Jun 15, 2018
10 hours
Explanation:
the solution is independent of the volume (content) of the tank, but for better understanding, let's assume the tank contains A litres.
filling A litres in 6 hours means the filling speed is
emptying A litres in 15 hours means the emptying speed is
So the net speed, when both filling and emptying at the same time is:
This means that our tank with A litres will be full in 10 hours