Speed of a boat in standing water is 8 kmph and the speed of the stream is 6 kmph. A man rows to place at a distance of 210 km and comes back to the starting point. The total time taken by him is: Choose the correct choice from the following:
A) 120 hours B) 240 hours C) 160 hours D) 480 hours E) none

Rationale: "sol . speed upstream = 2 kmph ; speed downstream = 14 kmph . ∴ total time taken = [ 210 / 2 + 210 / 2 ] hours = 120 hours . answer a"
Answer: A