To find the time taken to reach warehouse from factory we need to find the relative position of factory and Warehouse. Consider the speed be constant.
(1) It takes 15 minutes to drive from the factory to the harbor.
Case 1) F – – – – – – – ‒ → H – – – – – – – ‒ → W
Case 2) F – – – – – – ‒ – → W – – ‒ – ‒ – – ‒ → H
Case 2) H ← – – – – – – – – F – – – – – – – ‒ → W
Where \(F → H = 15\) minutes and \(F → W > 15\) or \(F → W < 15\) or \(F → W = 15\).
Clearly, INSUFFICIENT.
(2) It takes 25 minutes to drive from the warehouse to the harbor.
Case 1) W – – – – – – – – – ‒ → H ← – – – – – – – – ‒ ‒ F
Case 2) W ← – – – – – – – – ‒ → F – – – – – – – – – ‒ → H
Case 3) F – – – – – – – – – – ‒ → W – – – – – – – – – ‒ → H
Where \(W → H = 25\) minutes and \(F → W > 25\) or \(F → W < 25\) or \(F → W = 25\)
Clearly, INSUFFICIENT.
Together 1) and 2)
Case 1) W – – – – – – – – – – ‒ → H ← – – – – – – – ‒ F
Thus, \(F → W = 25 + 15 = 40\)
Case 2) W – – ‒ → F – – – – – ‒ → H
Thus, \(F → W = 25 - 15 = 10\)
Clearly, INSUFFICIENT.
Answer (E).
PS: Broken arrows length show approx. time taken.