a car travelled 60 km west in 1.33 h along straigt line, then returned back east for 40 km in 0.67 h. its average velocity

7.29 km/h East

Explanation:

Velocity is distance covered per unit time, with consideration to the direction.

Taking East as positive then West is negative

Velocity when traveling towards West

V=d/t where d is distance and t is time taken. Substituting 60 km dor d and 1.33 for t then

V=-60/1.33=-45.112781954887 km/h West

Velocity when traveling towards East

V=d/t where d is distance and t is time taken. Substituting 40 km dor d and 0.67 for t then

V=40/0.67=59.701492537313 km/h East

Average velocity = (velocity East+West) / 2

Average velocity is (59.701492537313+-45.112781954887) / 2=7.29 km/h

Since the average is positive, then the direction is East

Therefore, the average velocity is 7.29 km/h East