Speed of a boat in still water is 5 km/hr and speed of the stream is 2 kmph. A man rows to a place at a distance of 252 km and comes back to the starting point the total time taken by him is.	Pick one:
A) 160 hr  B) 200 hr  C) 120 hr  D) 140 hr  E) 180 hr

Rationale: explanation : speed up stream = 5 - 2 = 3 km / hr speed down stream = 5 + 2 = 7 km / hr total time taken = 252 / 3 + 252 / 7 = 84 + 36 = 120 hr answer : option b
Answer: B