SOLUTION: You buy 3 pencils and 1 pen for $1.75. You buy 2 pencils and 2 pens for $2.50. How much will 5 pencils cost?

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Question 255881: You buy 3 pencils and 1 pen for $1.75. You buy 2 pencils and 2 pens for $2.50. How much will 5 pencils cost?
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
3x+1y=1.75 muliply by -2 & add.
2x+2y=2.50
-6x-2y=-3.50
----------------
-4x=-1.00
x=-1.00/-4
x=$.25 cost of 1 pencil.
3*.25+y=1.75
.75+y=1.75
y=1.75-.75
y=$1.00 cost of i pen.
Proof:
2*.25+2*1.00=2.50
.50+2.00=2.50
2.50=2.50
5*.25=$1.25 is the cost of 5 pencils.