A car travels from city A to city B at a speed of 40 km/h and returns from city B to city A at a speed of 60 km/h. What is the average velocity of the car for the entire journey?

For the entire journey from city A to city B and back to city A, the initial position is city A and the final position is also city A. Therefore, the total displacement of the car is zero.

Average Velocity = Total Displacement / Total Time
Since Total Displacement = 0,
Average Velocity = 0 / Total Time = 0 km/h.