Question

Gillian purchased 25 books at the library book sale. Each hardcover book cost $1.50, and each paperback book cost $0.50. Gillian spent a total of $26.50. The book costs can be represented by the system of equations below.

h + p = 25
1.50h + 0.50p = 26.50
How many paperback books did Gillian buy?

11
12
13
14

Answer 1

Let h = number of hardcovers and p = number of paperbacks.

h + p = 25
1.5h + 0.5p = 26.5 → multiply by 2: 3h + p = 53

Subtract the first equation (h + p = 25) from that: 2h = 28 → h = 14

Then p = 25 − 14 = 11.

Answer: 11.