Answer: The average speed is 5.71 m/s
Step-by-step explanation:
The average speed in this run will be the quotient between the total distance that the runner traveled, and the total time it took.
Distance = 400m + 400m + 800m = 1600m
Time = 80s + 70s + 130s = 280s
Then the average speed is:
S = 1600m/280s = 5.71 m/s