If a person travels a certain distance at a speed of 10 km/h, and returns through the same route at a speed of 20 km/h, then what will be the average speed during the whole journey?
average speed during the whole journey =Â $$\frac{2\times speed_1\times speed_2\ }{speed_1+speed_2}$$
=Â $$\frac{2\times10\times20\ }{10+20}$$
= $$\frac{400\ }{30}$$
=Â $$\frac{40\ }{3}$$ km/h
Create a FREE account and get: