Question

Nakisa spent 328 on a total of CDs and DvDs. If Cds coat 12.00 and DVDs coat 16.00 each, how many CDs did Nakisa buy?

Answer 1

`c=(82)/(3)-(4)/(3)d`

Explanation:

1) Set up an equation

Let c be the number of CDs Nakisa bought.

Let d be the number of DVDs Nakisa bought.

`328=12c+16d`

Explanation: Each CD costs $12 and each DVD costs $16. Nakisa spent $328 altogether, which means $12c+$16d is equal to $328.

The question is asking for the number of CDs that Nakisa bought, so our goal is to isolate c in the equation above.

2) Isolate c

`328=12c+16d`

Subtract both sides by 16d

`328-16d=12c+16d-16d\\328-16d=12c`

Divide both sides by 12

`(328-16d)/(12)=(12c)/(12) \\(82)/(3)-(4)/(3)d=c`

`c=(82)/(3)-(4)/(3)d`

I hope this helps!