ABC Bookstore sells packages of books that include both new and used
books. New books cost $15 and used books cost $7. The bookstore wants to
sell packages that have 32 books total, and the store charges $320 for each package

A . 15 New , 7 used
B. 20 New , 12 used
C. 12 New , 20 used
D. 7 New , 15 used