Answer:
7.5 miles per hour
Step-by-step explanation:
Average speed over the interval [1, 3] = (distance at 3 hrs -distance at 1 hr)/(3 hrs - 1 hr)
From the graph:
Distance at 3 hrs = 30 => (3, 30)
Distance at 1 hr = 15 => (1, 15)
Average speed = (30 - 15)/(3 - 1)
Average speed = 15/2
= 7.5
Therefore, average speed = 7.5 miles per hour
