Give stream of consciousness and then the final answer. A man can row a boat at 10 kmph in still water and the speed of the stream is 8 kmph. What is then time taken to row a distance of 90 km down the stream ?
Options:
(A) 8hrs
(B) 5 hrs
(C) 15 hrs
(D) 15 hrs
(E) 20 hrs
Speed in down stream = 10 +8 = 18
Time taken to cover 90 km down stream = 90/18 = 5 hrs.
The final answer: (B).