12. A music store is selling cds for $11.50 and $7.50. You buy 12 discs and spend a total of

$106. How many cds that cost $11.50 did you buy?

4

Step-by-step explanation:

Let variable x represent the number of $11.50 CDs

If you buy a total of 12 discs, the number of $7.50 CDs would be (12-x).

Total amount spent = $106

Therefore, 11.50x + 7.50 (12-x) = $106

Next, open the parentheses and solve for x;

11.50x + 90 - 7.50x = 106

11.50x-7.50x = 106-90

4x = 16

divide both sides by 4 to solve for x.

x = 16/4

x=4

Since we let variable x to represent the number of $11.50 CDs, it means that you bought 4 of them.