In general you calculate average speed by taking the total distance traveled and dividing by the total time it took.

For example, let's say you get in your car and drive 40 miles in 1 hour, then you get to the interstate and drive an additional 140 miles in 2 hours. If you want to know your average speed throughout the trip, you'd take the total distance you traveled (180 miles) and divide by the total time (3 hours), for a result of 60 miles per hour average speed.


average speed = total distance / total time