Question

A store sells hardcover books for $8 and paperback books for $5. You buy 9 books, represented by the equation x+y=9, where x is the number of hardcover books and y is the number of paperback books. The equation 8x+5y=51 represents the total cost. How many of each type of book did you buy?

Answer 1

Explanation:

x+y = 9

y = 9-x

8x + 5y = 51

8x + 5(9-x) = 51

8x + 45 - 5x = 51

3x = 6

x = 2

y = 9-x = 7

Two hardcover books and seven paperback books.