A swimmer can swim in still water at 4 km/h. If the speed of the water current is 2 km/h, how many hours will the swimmer take to swim against the current for 8 km?  Answers:
A) 1 B) 2 C) 3 D) 4 E) 5

Rationale: "the swimmer can swim against the current at a speed of 4 - 2 = 2 km / h . the time it will take is 8 / 2 = 4 hours . the answer is d ."
Answer: D