If Parker wants to run 10 miles, he will have to run 28 more laps.
The track is 1/4 of a mile, meaning 4 laps around the track will equal 1 total mile. If he wants to run 10 miles, with 4 laps equaling 1 mile, then it would take 40 (10•4) laps in all. He has already ran 12 miles, so next we take 12 away from 40 (40-12), which equals 28.
Hope this helps.