Question

Mark averaged 60 miles per hour during the 30-mile trip to college. Because of heavy traffic he was able to average only 30 miles per hour during the return trip. What was Mark's average speed for the round trip?

Answer 1

Solution:

We are given that:

Mark averaged 60 miles per hour during the 30-mile trip to college.

Thus time required to cover 30-mile trip = 30 / 60 = 0.5 hour.

Because of heavy traffic he was able to average only 30 miles per hour during the return trip.

Thus time required for return trip = 30 / 30 = 1 hour.

Thus total distance = 30 + 30 = 60 miles and total time = 0.5 hour + 1 hour = 1.5 hour.

Thus

Mark's average speed for the round trip = 60 / 1.5

Mark's average speed for the round trip = 40 miles per hour.