A person can swim in still water at 12 km/h. If the speed of water 10 km/h, how many hours will the man take to swim back against the current for 8km?  Answers:  A) 4  B) 7  C) 5  D) 9  E) 6

Rationale: "m = 12 s = 10 us = 12 - 10 = 2 d = 8 t = 8 / 2 = 4 answer : a"
Answer: A