SOLUTION: A developer bought 900 acres of land for 680,000$. Some was bought at 600$ per acre, some for 800$ per acre and some for 1000$ per acre. How much of each did her buy if he bought t

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Question 1103055: A developer bought 900 acres of land for 680,000$. Some was bought at 600$ per acre, some for 800$ per acre and some for 1000$ per acre. How much of each did her buy if he bought twice as many acres at 600$ as he did at 1000$?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
A-amount of $600/acre land
B-amount of $800/acre land
C-amount of $1000/acre land
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1.A%2BB%2BC=900
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600A%2B800B%2B1000C=680000
2.3A%2B4B%2B5C=3400
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3.A=2C
Substituting eq. 3 into eqs. 1 and 2,
2C%2BB%2BC=900
4.B%2B3C=900
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3%282C%29%2B4B%2B5C=3400
6C%2B4B%2B5C=3400
5.4B%2B11C=3400
Multiply eq. 4 by 4 and subtract from eq. 5,
4B%2B11C-4B-12C=3400-3600
-C=-200
C=200
Now work backwards, use the equations and solve for B and A.