ABC Bookstore sells one customer 12 used books and 4 new books for $136.
Another customer buys 14 used books and 2 new books for $124. How much
is one used book (u), and one new book (n)?
OA. u= $13, n = $7
O B. u = $14, n = $2
O C. u= $12, n = $4
OD. u= $7, n= $13