A man can row downstream at the rate of 30 Kmph and upstream at 10 Kmph. Find the man’s rate in still water and rate of current?	Choose the most appropriate option:
A) 10
B) 8.0
C) 9.5
D) 9.0
E) 8.25

Rationale: "rate of still water = 1 / 2 ( down stream + upstream ) = 1 / 2 ( 30 + 10 ) = 20 kmph rate of current = 1 / 2 ( down stream - upstream ) = 1 / 2 ( 30 - 10 ) = 1 / 2 ( 20 ) = 10 kmph answer is a ."
Answer: A