Then, divide the sum by two. This will give you the average speed for the entire trip. So, if Ben traveled 40 mph for 2 hours, then 60 mph for another 2 hours, his average speed is 50 mph.
The time of travel between neighboring dots is always the same. But the distance between the dots changes. So, the speed between neighboring dots changes according to the formula. In most cases, this speed is not the same as the average speed in part F.