Kate bought 3 CDs and 1 DVD at a store. Her friend Joel bought 2 CDs and 2 DVDs. If Kate spent $20 and Joel spent $22, determine the cost of a CD and DVD.

Question

~Please provide an explanation as well.
Please and thanks!

Answer 1

cost of CD --- x
cost of DVD -- y

3x + y = 20 ---> y = 20-3x

2x + 2y = 22
x +y = 11
use substitution:
x + (20-3x) = 11
-2x = -9
x = 4.5
then y = 6.5