A person can swim in still water at 10 km/h. If the speed of water 8 km/h, how many hours will the man take to swim back against the current for 16km?
Choose the correct choice from the following answers
A) 3 B) 7 C) 5 D) 8 E) 6

Rationale: "m = 10 s = 8 us = 10 - 8 = 2 d = 16 t = 16 / 2 = 8 answer : d"
Answer: D