Question

Ms. Heaven had a gift card with a $400 balance. She bought several CDs that cost $21 each. After the purchase, her gift card balance was $232. Which equation can be used to determine the number of CDs (d) she purchased?

a) 400 - 21d = 232
b) 400 + 21d = 232
c) 400 - d = 232
d) 21d - 400 = 232

Answer 1

The correct equation to determine the number of CDs Ms. Heaven purchased is 400 - 21d = 232, since each CD costs $21 and this is the total price subtracted from her initial gift card balance.

Step-by-step explanation:

To determine the number of CDs (d) Ms. Heaven purchased, we need to set up an equation where the initial gift card balance minus the total cost of CDs equals the remaining balance. Each CD costs $21, so the cost for d CDs would be 21 times d, or 21d. Ms. Heaven's initial balance was $400, and after the purchases, her balance was $232. Therefore, the equation to represent this situation is:

400 - 21d = 232

To solve for d, you would subtract 400 from both sides to get -21d = -168, then divide by -21 to find d, the number of CDs purchased:

d = 8