Answer:
25 m/s
Explanation:
Average speed is equal to the total distance divided by the total time. By assuming a total distance, we can calculate the time it takes the car to drive that distance, then find the average speed.
The car travels one third of the path at 50 m/s, and two thirds of the path at 20 m/s. If we say that the path is 300 meters long, then we can find the time spent at each speed.
The time the car travels the first 100 meters is:
t₁ = (100 m) / (50 m/s) = 2 s
The time the car travels the next 200 meters is:
t₂ = (200 m) / (20 m/s) = 10 s
The total time the car travels is therefore:
t = 2 s + 10 s = 12 s
So the car's average speed is:
(300 m) / (12 s) = 25 m/s