So first you need to understand the idea that distance = rate * time. For the first half hour he runs at 5.5 mph, which means you take .5 hours (half an hour) and multiply by the speed (5.5mph) to get his total distance covered..5 * 5.5 = 2.75 miles. so 2.75 + 1.5p = 13.25 is the equation. Solve this to get his rate for the final 1.5 hours1.5p = 10.5p = 7