Phineas is shopping for books at a mega book sale. He has a $275 gift card that expires today, so he wants to get as many books as he can while also spending as much of the money as possible. However, the sale has a limit of 15 books per customer. Special-edition books are on sale for $25 each, and all other books are on sale for $15 each.
1. What number of special-edition and regular books should Phineas buy in order to buy as many books as he can and also use as much of his gift card money as possible (without going over the amount on the gift card or the limit of books)?
2. What remaining balance will Phineas have on the gift card after his purchase, if any?