Two dogsled teams raced across a 600-mile course in Alaska. Team A finished the course in 6 fewer hours than team B. If team A’s average speed was 5 miles per hour greater than that of team B, what was team B’s average speed, in miles per hour? Choices:
A) 12
B) 15
C) 18
D) 20
E) 25
Let v be team B's average speed.   Time = Distance/Rate and the time difference was 6 hours.   600/v - 600/(v+5)= 6   600v + 3000 - 600v = 6(v)(v+5)   500 = (v)(v+5)   (20)(25) = (v)(v+5)   v = 20 mph   The answer is 20.
<result>D</result>
Two dogsled teams raced across a 600-mile course in Alaska. Team A finished the course in 6 fewer hours than team B. If team A’s average speed was 5 miles per hour greater than that of team B, what was team B’s average speed, in miles per hour?