My daily 7 mile commute to work takes 10 minutes and includes instaneous speeds of 15 mph, 0 mph, 45 mph, and 70 mph. What is my average speed in mph?
Average Speed = Total distance covered / Elapsed time
Elapsed time =10 minutes / 60 minutes =1/6 of an hour
Average speed =7 miles / (1/6) hours
=7 x 6
= 42 mph - your average speed.
If you are travelling by bus, for example, the bus will stop at various "bus stops" and then drive at various speeds until you get to your destination. All that counts here is that you must know "total distance travelled" and the "elapsed time to cover that distance". Then you can calculate your average speed using the above formula.