physics
posted by anonymous .
A bicyclist starts a timed race at 6 mph In order to win, he must average 21 mph Assuming constant acceleration from the start, how fast must he be traveling at the end of the race?

If the average must be 21,
(V1 + V2)/2 = 21
V1 + V2 = 42
V2 = 42  V1 = 42  6 = ___ mph
V2 is the final velocity required
V1 is the initial velocity