SOLUTION: Eldora and Finn went to an office supply store together. Eldora bought 15 boxes of paper clips and 7 packages of index cards for a total cost of $55.40. Finn bought 12 boxes of pap

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Eldora and Finn went to an office supply store together. Eldora bought 15 boxes of paper clips and 7 packages of index cards for a total cost of $55.40. Finn bought 12 boxes of pap      Log On


   

Question 214745: Eldora and Finn went to an office supply store together. Eldora bought 15 boxes of paper clips and 7 packages of index cards for a total cost of $55.40. Finn bought 12 boxes of paper clips and 10 packages of index cards for a total cost of $61.70. Find the cost of one box of paper clips and the cost of one package of index cards.
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
15c+7i=55.40 multiply by -4
12c+10i=61.70 multiply by 5 & add
-60c-28i=-221.6
60c+50i=308.5
--------------------
22i=86.9
i=86.9/22
i=3.95 the cost of the index card package.
15c+7*3.95=55.40
15c+27.65=55.40
15c=55.40-27.65
15c=27.75
c=27.75/15
c=1.85 the cost of the box of paper clips.
Proof:
12*1.85+10*3.95=61.70
22.20+39.50=61.70
61.70=61.70