With both valves open, the pool will be filled with water in 48 minutes. The first valve

With both valves open, the pool will be filled with water in 48 minutes. The first valve alone would fill the pool in 2 hours. What is the capacity of the pool if every minute the second valve admits 50 cubic meters of water more than the first?
* 9000 cubic meters
* 10500 cubic meters
* 11750 cubic meters
* 12000 cubic meters
* 12500 cubic meters









Figure out the time Valve 2 took to fill the pool by itself
1/Valve1 + 1/Valve2 = 1/48
1/120 mins (or 2 hours) + 1/Valve2 = 1/48 mins
Valve2 = 80 mins

ie 120X = 80(x + 50) ==> x = 100.
We get x = 100.
Now substitute value of x in any of the 3 eq and you should get the total volume.
12000