Answer:
6.05 km/h
Explanation:
The average speed (v) is equal to the total distance (d) divided by the total time (t). Using the equation v = d / t, find the time spent walking and the time spent running, then add together to get the total time. Divide the total distance by the total time to get the average speed, and finally convert meters per second to kilometers per hour.
The time spent walking is:
v = d / t
1.15 m/s = 71.92 m / t
t = 71.92 m / 1.15 m/s
t = 62.54 s
The time spent running is:
v = d / t
3.09 m/s = 72.68 m / t
t = 72.68 m / 3.09 m/s
t = 23.52 s
The total distance is:
d = 71.92 m + 72.68 m
d = 144.6 m
The total time is:
t = 62.54 s + 23.52 s
t = 86.06 s
So the average speed is:
v = d / t
v = 144.6 m / 86.06 s
v = 1.68 m/s
Convert m/s to km/h.
v = 1.68 m/s × (1 km / 1000 m) × (3600 s / h)
v = 6.05 km/h