Working independently at their respective constant rates, pumps \(X\) and \(Y\) took \(48\) minutes to fill an empty tank with water. What fraction of the water in the full tank came from pump \(X?\)
(1) Working alone at its constant rate, pump \(X\) would have taken \(80\) minutes to fill the tank with water.
(2) Working alone at its constant rate, pump \(Y\) would have taken \(120\) minutes to fill the tank with water.
Answer: D
Source: GMAT Prep