Question

A man travels half length of a straight road with a constant speed of 20m/s and he travels the second half with a constant speed of 60m/s,then calculate average speed.

Answer 1

Let each 1/2 the distance be 1000m. Then:

1000m/ 20 m/s=50 secs

1000m/60 m/s=1/3 * 50 secs=50/3 secs

2000 m/ 200/3 secs=30 m/s as the average