Question

Phillip bought 12 used CDs and DVDs. CDs cost $2 each and DVDs cost $3 each. He spent $31 not including tax. How many DVDs did Phillip buy?

A. 10

B. 7

C. 5

D. 2

Answer 1

We will end up with two equations:
31 = 2x + 3y
to represents the money he spent
where x is cds and y is dvds

but we also have the equation:

C + D = 12
to represent how many he bought.

we want the number of number of dvds, so first solve for D

Answer 2

B. 7

Answer 3

Thankyou both!!