Use some thinking to answer the following question. A man rows his boat 120 km downstream and 60 km upstream, taking 2 hours each time. Find the speed of the stream?
Options:
(A) 6
(B) 15
(C) 17
(D) 18
(E) 2
Speed downstream = d/t = 120/(2 ) = 60 kmph
Speed upstream = d/t = 60/(2) = 30 kmph
The speed of the stream = (60 - 30)/2 = 15 kmph So the final answer is (B).