A motor boat takes 12 hours to go downstream and it takes 24 hours to return the same distance. what is the time taken by boat in still water?  Choose the correct choice from the following answers
A) 26 h B) 16 h C) 86 h D) 96 h E) 66 h

Rationale: explanation : if t 1 and t 2 are the upstream and down stream times . then time taken in still water is given by \ inline \ frac { 2 \ times t 1 \ times t 2 } { t 1 + t 2 } = \ frac { 2 \ times 12 \ times 24 } { 36 } = 16 h answer : b
Answer: B