A man can row upstream at 15 kmph and downstream at 35 kmph, and then find the speed of the man in still water? Choose the correct choice from the following options.
A) 65
B) 86
C) 30
D) 78
E) 25

Rationale: "us = 15 ds = 35 m = ( 35 + 15 ) / 2 = 25 answer : e"
Answer: E