A man can row upstream at 45 kmph and downstream at 55 kmph, and then find the speed of the man in still water?  Choose the correct choice from the following:
A) 32 kmph
B) 34 kmph
C) 30 kmph
D) 50 kmph
E) 65 kmph

Rationale: "us = 45 ds = 55 m = ( 45 + 55 ) / 2 = 50 answer : d"
Answer: D