Stream of consciousness rationale: Speed downstream = d/t = 65/(2 1/2) = 26 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (26 - 18)/2 = 4 kmph
The question and answer pair are described below.
Q: A man rows his boat 65 km downstream and 45 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?
Options:
(A) 5 kmph
(B) 4 kmph
(C) 9 kmph
(D) 8 kmph
(E) 1 kmph
A: (B)