<u>Answer:</u> The average speed of the roller coast is 30 m/s
<u>Explanation:</u>
Average speed is defined as the ratio of total distance traveled to the total time taken.
To calculate the average speed of the runner, we use the equation:

We are given:
Total distance traveled by roller coast = 3000 m
Total time taken = 100 seconds
Putting values in above equation, we get:

Hence, the average speed of the roller coast is 30 m/s