A man can row upstream at 27 kmph and downstream at 35 kmph, and then find the speed of the man in still water?  Choose the correct choice from the following:
A) 31
B) 92
C) 30
D) 32
E) 23

Rationale: "us = 27 ds = 35 m = ( 35 + 27 ) / 2 = 31 answer : a"
Answer: A