Question

A car travels north along a certain highway at a constant speed of 40 miles per hour. It immediately turns around and returns south along the same highway at a constant speed of 50 miles per hour. What was its average speed for the entire round trip? (Hint: the answer is NOT 45 miles per hour)

Answer 1

44.44 mph/44 4/9

Explanation:

It asks for distance and not time. If it said it travels 1 mile each way then it won't be 45 mph. If it was 1 hour one way and an hour back then it would be different distances but 45 mph.

We can just say the car traveled 40 miles and use it for this equation.

40 mph for 40 miles is 1 hour

50 mph for 40 miles is 48 minutes

48+60 minutes is 108

This is 44.44 miles per hour

or 44 4/9 if you want to show it more accurately