Two dogsled teams raced across a \(300\)-mile course in Wyoming. Team \(A\) finished the course in \(3\) fewer hours

[Vincen]

Two dogsled teams raced across a \(300\)-mile course in Wyoming. Team \(A\) finished the course in \(3\) fewer hours than team \(B.\) If team \(A\)'s average speed was \(5\) mph greater than team \(B\)'s, what was team \(B\)'s average mph?

A. 12
B. 15
C. 18
D. 20
E. 25

Answer: D

Source: GMAT Prep