#### Answer

40km/h

#### Work Step by Step

Velocity is defined as displacement over time, therefore average velocity will just be the total displacement divided by the total amount of time. We know from the question that the total displacement is 80km, therefore we need to find the total time it took.
There are two segments:
The car travels 40km at 30km/h
The car travels 40km at 60km/h
The time the car spent in the first segment can be found by taking the 40km and dividing it by the 30km/h, which gives us 1.33 hours.
The time the car spent in the second segment can be found by taking the other 40km and dividing it by the 60km/h, which gives us 0.667 hours.
The total hours spent is 2 hours. Therefore we have 80km driven in 2 hours for an average velocity of 40km/h