A bookstore that sells used books sells each of its paperback books for a certain price and each of its hardcover books for a certain price. If Joe, Maria, and Paul bought books in this store, how much did Maria pay for 1 paperback book and 1 hardcover book?
(1) Joe bought 2 paperback books and 3 hardcover books for $12.50.
(2) Paul bought 4 paperback books and 6 hardcover books for $25.00.