At best buy, Larry buys three CDs and three DVDs for $96 from the sale rack. Kelly buys two CDs and one DVD from the same rack for $44. What is the price per CD and the price per DVD?

Question

anonymous · Answer

First things first - go ahead and change the problem into a mathematic notation.  Let's call CDs x and DVDs y.

3x+3y = 96
2x+1y = 44

Then we just solve our way for each variable through this linear system!

anonymous · Answer

thanks I do not know if I am correct but when I solved I got the answer x=32

anonymous · Answer

It's a bit too high for x.  Because then we'd have y = 0 in the first equation and 66 = 44 in the second.

Let's look at the second equation first 2x+1y = 44

First things first, let's solve for y here, just because it's easy.  Move 2x to the right hand side by subtracting it from each side... 

We now have y = 44 - 2x.

Solve for y in the first equation, and you'll see a pattern appear in the two, that'll help solve it.

anonymous · Answer

x=12 and y=20

anonymous · Answer

Fantastic!    Good job!