Final answer:
The average rate of change (speed) for Mrs. Garvin's trip from north of Orlando to New York is 10 miles per hour.
Step-by-step explanation:
The average rate of change (speed) can be calculated by dividing the change in distance by the change in time. In this case, Mrs. Garvin starts 90 miles north of Orlando and drives for 8 hours. From the graph, we can see that her distance from Orlando decreases by 80 miles during this time period (90 miles - 10 miles). Therefore, her average rate of change (speed) is 80 miles / 8 hours = 10 miles per hour.