Rani covers a certain distance by car driving at 5 km/h

Rani covers a certain distance by car driving at 5 km/h and returns the starting point riding on a scooter at 2 km/h. Find her average speed for the whole journey.

According to the formula,
Average speed = 2AB/(A + B)
Here, A = 5 km/h, and B = 2 km/h
∴ Required average speed = (2 x 5 x 2)/7 = 20/7
= 2⁶/₇ km/h