Question 1017204: The cost for three packages of moving boxes is modeled by the system of equations below. Let s represent small boxes, m represent medium boxes, and l represent large boxes. Which ordered pair (s, m, l) represents the costs of the three boxes?
7s+4m+2l=24
5s+3m+6l=30
3s+7m+10l=46
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! 7s+4m+2t =24
5s+3m+6t =30
3s+7m+10t=46
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Subtract 2 times the 3rd row from row 1 to get:
s - 10m - 18t = -68
5s+3m+6t =30
3s+7m+10t=46
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Subtract 5 times the 1st row from the 2nd row
Subtract 3 times the 1st row from the 3rd row
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s - 10m - 18t = -68
0s + 53m + 96t = 370
0s + 37m + 64t = 250
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Multiply thru 2nd row by 37
Multiply thru 3rd row by 53
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s - 10m - 18t = -68
0s + 1961m + 3552t = 13690
0s + 1961m + 33924m = 13250
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Subtract 2nd row from 3rd to get::
s - 10m - 18t = -68
0s + 1961m + 3552t = 13690
0s + 0m - 160t = -440
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Solve the 3rd row for "m"::
s - 10m - 16t = -68
0s + 1961m + 3182t = 13690
0s + 0m + t = 2.75
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Substitute for "t" in row 2 and solve for "m":: m = 2
Substitute for "t" and for "m" in row 1 and solve for "s":: s = 1.5
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Cheers,
Stan H.
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