A cyclist bikes x distance at 20 miles per hour and returns over the same path at 16 miles per hour. What is the cyclist's average rate for the round trip in miles per hour?	Choose the correct choice from the following:
A) 17.6  B) 17.3  C) 8.6  D) 17.2  E) 9.0

Rationale: "distance = d 1 = x miles speed = s 1 = 20 miles per hour time = t 1 = distance / speed = x / 20 2 . going from b to a distance = d 2 = x miles speed = s 2 = 16 miles per hour time = t 2 = distance / speed = x / 16 3 . average speed = total distance / total time total distance = x + x = 2 x total time = x / 20 + x / 16 = 9 x / 80 speed = 2 x / ( 9 x / 80 ) = 160 / 9 = 17.6 answer : a"
Answer: A