David M. answered 11/24/18
Dave "The Math Whiz"
The average speed will be the total distance traveled divided by the total time in doing so. The total distance will be 100 + 100 = 200 m. The total time will be how long it took to run 100 m + how long it took to walk 100 m.
Run: (100m)/(5m/s)=20s
Walk: (100m)/(1m/s)=100s
Total time: 20+100=120s
Average speed = 200m/120s
=1.67m/s