Question

The distance between two cities is 30 km. a man goes at a speed of 30 km per hour and returns at 20 km per hour. what is his average speed?

Answer 1

Average speed = 2v1v2 / (v1 + v2)
= 2 * 30 * 20 / (30 + 20)
= 24 km/h

Average speed of man is 24 km/h