Find your true average speed for a trip made up of several legs, each at a different speed and distance.
Averaging speeds directly (like (60+40)/2 = 50) is wrong when the legs cover different amounts of time. The correct average is total distance divided by total time.
Average Speed = Total Distance ÷ Total Time, where each leg's time is calculated as Distance ÷ Speed.
60 miles at 60 mph (1 hour) plus 40 miles at 40 mph (1 hour) covers 100 miles in 2 hours - a true average speed of 50 mph, which happens to match here only because the times were equal.
It's total distance traveled divided by total time taken — not simply the average of each leg's speed.
Because legs of different distances or durations contribute unequally to the trip; a short fast leg and a long slow leg don't average out evenly if you just average the two speed values.
Use consistent distance units (all miles or all km) and consistent time units across every leg for an accurate total.