Problem 8.

We drive a distance of 1 km at 16 km/h. Then we drive an additional distance of 1 km at 32 km/h. What is our average speed?

Solution:

By definition the average speed is the ratio of traveled distance and traveled time.

The traveled distance is 2 km.

The traveled time is the sum of two contributions:

•  time of the motion a distance 1 km with speed 16 km/h. It is

•  time of the motion a distance 1 km with speed 32 km/h. It is

Then the average speed is