Well, you get 2n miles for each of the first 3 days and n miles for each of the other 4. That is, 2n+2n+2n+n+n+n+n=56.5. That is, 10n=56.5 or n=5.65 miles each of the last 4 days. The first 3 days, Luke jogged double that, that is, 11.3 miles each day.
