Answer:
10.89
Explanation:
The total distance traveled is 1960 m.
400 + 1200 + 360 = 1960
Now, you have to find the time it took to travel each distance.
400 ÷ 8 = 50
1200 ÷ 12 = 100
360 ÷ 12 = 30
The total time it took travel the distance is 180 s.
50 + 100 + 30 = 180
To find the average speed, divided the total distance traveled by the total time.
1960 ÷ 180 = 10.89 s