SOLUTION: Carla goes to Bargain Music and buys 4 used CDs and 7 new CDs. She pays a total of $65. Later, Tim goes to Bargain Music and pays $33 for 4 used Cds and 3 new Cds. The equations

Algebra ->  Algebra  -> Expressions-with-variables -> SOLUTION: Carla goes to Bargain Music and buys 4 used CDs and 7 new CDs. She pays a total of $65. Later, Tim goes to Bargain Music and pays $33 for 4 used Cds and 3 new Cds. The equations       Log On

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Question 11834: Carla goes to Bargain Music and buys 4 used CDs and 7 new CDs. She pays a total of $65. Later, Tim goes to Bargain Music and pays $33 for 4 used Cds and 3 new Cds.
The equations below can be used to determine the cost of a used CD (x) and the cost of a new CD (y).
4x+7y=65
4x+3y=33
What are the costs of the two CDs?
these are the answeres
$2.25 per used CD and $8 per new CD
I don't know how they got that answere and if you could explain it to me, I would very much appritiate it. Thanks!
Answer by elima(1433) About Me  (Show Source):
You can put this solution on YOUR website!
4x+7y=65
4x+3y=33
You begin by find the value of one of the variables. In this case lets take the equation:
4x+3y=33
you solve the equation for x:
4x=33-3y
x=33-3y%2F4
Then you replace the x in the other equation:
4%2833-3y%29%2F4%2B7y=65
Cancel out the 4's you end up with:
33-3y+7y=65
THen you will subtract 33 from both sides:
-3y+7y=32
Then add like terms:
4y=32; divide both sides by 4,
and you end up with:
y=8
Now you have the answer for one variable, so you place that in one of the equations,
4x+3y=33
4x+3(8)=33
4x+24=33
4x=9
x=9/4=2.25