Practice!

Sample Problem

A truck covered 2/7 of a journey at an average speed of 40 mph. Then, it covered the remaining 200 miles at another average speed. If the average for the whole journey was 35 mph, what was the amount of time for the whole journey?

  h

Solution

The remaining 200 miles was (1 - 2/7 = 5/7) of the total journey.

Then, total distance: 200 ÷ 5/7 = 200 × 7/5 = 280 miles

Recall the formula: Distance ÷ Speed = Time

Thus, the total time: 280 ÷ 35 = 8 h