A: Speed downstream = 6 kmph Time taken = 72/6  20 = 36 hours. The answer is (B).
Answer the following multiple choice question with options (a), (b), (c), (d), (e) by reasoning step-by-step.
Q:A man can row a boat at 20 kmph in still water. If the speed of the stream is 6 kmph, what is the time taken to row a distance of 72 km downstream? Answer Choices: A)30/16 hours B)36/13 hours C)30/73 hours D)30/13 hours E)50/13 hours