A publisher needs to send many books to a local book retailer and will send the books in a combination of small and large boxes. Each small box can hold
20 books and each large box can hold 30 books. A total of 9 boxes were sent
which can hold 240 books altogether. Graphically solve a system of equations
in order to determine the number of small boxes sent, X, and the number of
large boxes sent, y.