A bicyclist starts a timed race at 6.0 mi/h.In order to win,he must average 21 mi/h.Assuming constant acceleration from the start,how fast must he be traveling at the end of the race?
A)36 mi/h
B)30 mi/h
C)24 mi/h
D)42 mi/h

Question

Quizplus · Accepted Answer

To average 21 mi/h over the entire race, the final speed must be such that the average of the initial speed (6 mi/h) and the final speed equals 21 mi/h. Solving the equation (6 + final speed) / 2 = 21 gives a final speed of 36 mi/h.

A Bicyclist Starts a Timed Race at 6