Joseph traveled from Boston to Framingham at 50 mph and then back to Boston at 40 mph. What was Joseph's average speed on the round trip?

Answer 1

Key fact:
the distance is the same each way

time to go from B to F = d/50
time to go from F to B = d/40

avg speed = total distance/total time
= 2d/(d/50 + d/40)
= 2d/[(4d + 5d)/200]
= 2d * (200)/9d
= 400/9 or appr 44.4 mph

Answer 2

Joseph traveled from Boston to Framingham at 50 mph and then back to Boston at 40 mph. What was Joseph's average speed on the round trip?