At a garage sale, Samuel purchased used books and DVDs. He bought a total of 18 items and spent $11. Each book cost $0.50 and each DVD cost $0.75. How many books did Samuel purchase?

10 books

Step-by-step explanation:

Let the number of books bought be represented by x.

Let the number of dvds bought be represented by y.

The information given in the question can be formed into an equation as:

x + y = 18 i

0.50x + 0.75y = 11 ii

Multiply equation i by 0.75

Multiply equation ii by 1

0.75x + 0.75y = 13.50 iii

0.50x + 0.75y = 11 iv

Subtract iv from iii

0.25x = 2.50

x = 2.50/0.25

x = 10

Samuel bought 10 books

$9.89

step-by-step explanation:

9.90 = p x .06 x .25 (3/12 changed to a decimal)

9.90 = p x 0.015

9.90 - 0.015 = p

9.89 = p