Question

A car travels a certain distance at a speed of 50 km/h and returns with a speed of 40 km/hr. Calculate the average speed of the whole journey.

Answer 1

To complete $1km$ distance with speed $=50kmhr$ it tkes time $t_1=\frac{1}{50}s$

To complete $1km$ distance with speed $=40kmhr$ it tkes time $t_1=\frac{1}{40}s$

Average speed$=\frac{1+1}{\left(1/50\right)+\left(1/40\right)}=44.44m/s$