A man can row upstream at 15 kmph and downstream at 25 kmph, and then find the speed of the man in still water?  Choose the most appropriate option:	A) 27	B) 29	C) 30	D) 20	E) 24

Rationale: "us = 15 ds = 25 m = ( 15 + 25 ) / 2 = 20 answer : d"
Answer: D