SOLUTION: How much 90 percent vinegar do you have to add to a gallon of 5 percent vinegar to get 20 percent vinegar?

Question 898249: How much 90 percent vinegar do you have to add to a gallon of 5 percent vinegar to get 20 percent vinegar?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
How much 90 percent vinegar do you have to add to a gallon of 5 percent vinegar to get 20 percent vinegar?
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Equation:
vinegar + vinegar = vinegar
0.90x + 0.05*1 = 0.20(x+1)
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90x + 5 = 20x + 20
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70x = 15
x = 15/70 = 0.21 gallons (amt. 90% solution needed)
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Cheers,
Stan H.
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