1). The first green circle on the graph, at 1 hr, is up at 40 miles.
2). (40 miles) / (1 hour) = 40 mph
3). The distance doesn't change during the second hour. They didn't travel at all during that hour.
4). Average speed = (distance covered) / (time to cover the distance) = 40 miles / 2 hours = 20 mph during the first 2 hours
5). The greatest average speed is the period where the graph has the steepest slope. That's during the first hour.
6). The car was stopped during the whole 2nd hour and the whole 5th hour.
7). At the end of 3 hours, the graph has moved up to 60 miles. The average speed during those 3 hours is
(60 miles) / (3 hours) = 20 mph .
8). The farthest away from home they ever got was 76 miles. If they take 3 hours to return, over the same route, then their average speed on the return will be
(76 miles) / (3 hours) = (25 and 1/3) miles per hour.
