Question 1136822: how many liters of a 12% alcohol solution must be added to 15 liters of a 5% alcohol solution to get a mixture that is 8% alcohol? Answer by rothauserc(4718) (Show Source):
You can put this solution on YOUR website! let x be the number of liters needed to add to the 12% solution
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we have three relations, the third relation is the mixture
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1) x * 0.12 = 0.12x
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2) 15 * 0.05 = 0.75
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3) (x+15) * 0.08 = 0.08(x+15)
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0.12x +0.75 = 0.08(x+15)
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0.12x +0.75 = 0.08x +1.20
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0.04x = 0.45
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x = 11.25
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11.25 liters of the 12% solution is necessary
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check answer
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0.12(11.25) +0.75 = 0.08(11.25) +1.20
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1.35 +0.75 = 0.90 +1.20
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2.1 = 2.1
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also
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(11.25 + 15) * 0.08 = 2.1
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answer checks
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