Question 290177
A gallon of vinegar is labled 5% acidity. How many fluid Ounces of pure acid must be added to get 6% acidity?
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acid + acid = acid
0.5*1 + 1*x = 0.6(1+x)
0.5 + x = 0.6 + 0.6x
0.4x = 0.1
x = 1/4 gallon (amount of pure acid needed in the mixture)
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A 12% saline solution is to be deluted with water to obtain 20 oz. of a 10% solution. How much water is needed?
saline + saline = saline
0.12x + 0*(20-x)= 0.10*20
0.12x = 2
x = 16 2/3 
water = 20-16 2/3 = 3 1/3 oz (amount of water needed for the mixture)
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Cheers,
Stan H.