A motor cyclist participant of a race says "We drove with the speed of 10 miles an hour one way, but while returning because of less traffic we drove on the same route with 17 miles per hour." What was their average speed in the whole journey?
Answers
A) 10 miles/hour
B) 12 miles/hour
C) 11 miles/hour
D) 12.6 miles/hour
E) 14 miles/hour
2xy/x+y=12.6 miles/hour   ANSWER:12.6 miles/hour
<result>D</result>
A motor cyclist participant of a race says "We drove with the speed of 10 miles an hour one way, but while returning because of less traffic we drove on the same route with 17 miles per hour." What was their average speed in the whole journey?