A cyclist bikes x distance at 10 miles per hour and returns over the same path at 9 miles per hour. What is the cyclist's average rate for the round trip in miles per hour? Answers:
A) 8.1
B) 8.3
C) 8.6
D) 8.9
E) 9.5
Distance = d1 = x miles   Speed = s1 = 10 miles per hour   Time = t1 = Distance/ Speed = x/10   2. Going from B to A   Distance = d2 = x miles   Speed = s2 = 9 miles per hour   Time = t2 = Distance/ Speed = x/9   3. Average Speed = Total Distance/Total Time   Total Distance = x + x = 2x   Total Time = x/10 + x/9 = x (1/10 + 1/9) = x ( 4 + 5)/40 = 19x/90   Speed = 2x/(19x/90) = (2x * 90)/9x =180x/19x = 180/19 = 9.5   Answer : 9.5
<result>E</result>
A cyclist bikes x distance at 10 miles per hour and returns over the same path at 9 miles per hour. What is the cyclist's average rate for the round trip in miles per hour?