Question

Donovan is buying a number of copies of a book.

Cost (in dollars)

How much will it cost Donovan to buy 8 copies? Record the answer in dollar

Answer 1

$24.00

Explanation:

It cost $3.00 a book.

8 x 3 = 24

The graph is proportional. The cost per book would be any point on the graph in the form y/x.

For example the point (4,12) would be 12/4 = 3. This is the cost per book. I could have used the point (6,18) would be 18/6 = 3.