A person can swim in still water at 4 km/h. If the speed of water 2 km/h, how many hours will the man take to swim back against the current for 6km?  Choose the most appropriate option:
A) 3	B) 5	C) 6	D) 67	E) 7

Rationale: "m = 4 s = 2 us = 4 - 2 = 2 d = 6 t = 6 / 2 = 3 answer : a"
Answer: A