Speed of a boat in standing water is 16 kmph and the speed of the stream is 2 kmph. A man rows to a place at a distance of 7740 km and comes back to the starting point. The total time taken by him is:  Choose the correct choice from the following.
A) 914.2 hours B) 900 hours C) 915 hours D) 982.9 hours E) 915 hours

Rationale: "explanation : speed downstream = ( 16 + 2 ) = 18 kmph speed upstream = ( 16 - 2 ) = 14 kmph total time taken = 7740 / 18 + 7740 / 14 = 430 + 552.9 = 982.9 hours answer : option d"
Answer: D