Question

Reza brought old CDs and DVDs to sell for a school fundraiser. The CDs sold for $3 each, and the DVDs sold for $5 each. At the end of the day, the total sales for her CDs and DVDs was $45. Let c = number of CDs sold and d = number of DVDs sold.Which one of the following total CDs sold or total DVDs sold is possible?a. 8 DVDs soldb. 6 DVDs soldc. 4 CDs soldd. 12 CDs sold

Answer 1

b. 6 DVDs sold

Explanation:

• The number of CDs sold = c

,

• The number of DVDs sold = d

The CDs sold for $3 each, and the DVDs sold for $5 each.

Thus, the total sales is:

`3c+5d`

Given that the total sales for her CDs and DVDs was $45, then:

`3c+5d=45`

Option A: If 8 DVDs were sold, d=8

• 3c+5(8)=45

,

• 3c=45-40

,

• 3c=5

The value of c will not be a whole number, this option is incorrect.

Option B: If 6 DVDs were sold, d=6

3c+5(6)=45

3c=45-30

3c=15

c=5

The value of c is a whole number, this option is correct.

Note: Every other option will not give a whole number as in the case of Option A,