SOLUTION: A landscaper wants to combine golden landscape rock with rust-colored landscape rock to make a mix. The golden rock costs $0.59 per pound and the rust-colored rock cost $0.49 per p

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Question 183884: A landscaper wants to combine golden landscape rock with rust-colored landscape rock to make a mix. The golden rock costs $0.59 per pound and the rust-colored rock cost $0.49 per pound. If the landscaper buys 90 pounds of the mixture costing a total of $48.60, how much of the golden rock did he buy?
Answer by tvandenberg(45) About Me  (Show Source):
You can put this solution on YOUR website!
G = amount of golden rock
R = amount of rusted rock
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(a) G + R = 90
(b) 0.59*G + 0.49*R = 48.60
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We need to now solve (a) for either G or R, I randomly chose G...
(a') G = 90 -R
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Substitute (a') into (b)
(b') 0.59*(90-R) + 0.49*R = 48.60
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Some "simple" algebra...
53.10 - 0.59*R + 0.49*R = 48.60
4.50 = 0.1*R
R = 45
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Back to (a')...
G = 90 - 45 = 45
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Check your answers:
(a) 45 + 45 = 90 (good)
(b) 0.59*(45) + 0.49*(45) = 48.60 (good)