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 pa

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Question 674377: 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 ReadingBoosters(3246) About Me  (Show Source):
You can put this solution on YOUR website!
15p + 7c = 55.40
12p + 10c = 61.70
...
Multiply the first equation by 10 and the second by -7
10(15p+7c=55.40)
-7(12p+10c=61.70)
...
150p + 70c = 554
-84p - 70c = -431.90
Add the equations to solve for p
150p + -84p + 70c + -70c = 554 + -431.90
66p = 122.10
highlight_green%28p+=+1.85%29 cost of paper clips
...
15(1.85) + 7c = 55.40
27.75 + 7c = 55.40
7c = 55.40 - 27.75
7c = 27.65
highlight_green%28c+=+3.95%29 cost of index cards
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