Acar that travels from point a to point b in four hours, and then from point b back to point a in six hours. the road between point a and point b is perfectly straight, and the distance between the two points is 240 km. what is the car’s average velocity?

Note : Be careful with speed and velocity, even the formula is same that 

1. If we would like to find the velocity, we must calculate the distance from initial to final, ,

2. If we would like to find the speed, we must calculate the total distance that travelled (.

So, in this question, because it return back to its initial point so (delta)x = 0, so average velocity is 0 m/s.