A bicyclist started riding at 8:00a.m. the diagram below shows the distance the bicyclist had traveled at different times. What was the bicyclists average rate of speed in miles per hour? 8:00a.m (@ 4.5miles) to 8:15a.m. (@ 7.5 miles) to 8:45a.m.

I think that it is saying that 8:15-8:45 is 7.5 miles right? Then 8- 8:15 is 4.5 and you are trying to find the average of an HOUR. So in order to get an hour you need 15 more mins. Which is 4.5 miles according to the chart. (8-8:15). So 4.5+4.5+7.5=16.5. Divided by three is 5.5 miles per hour. I'm not sure but this is what I would do.