SOLUTION: how much pure acid should be mixed with 5 gallons of a 70% acidic solution in order to get a 90% acidic solution

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Question 859343: how much pure acid should be mixed with 5 gallons of a 70% acidic solution in order to get a 90% acidic solution
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
how much pure acid should be mixed with 5 gallons of a 70% acidic solution in order to get a 90% acidic solution
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Equation:
acid + acid = acid
1*x + 0.70*5 = 0.90(x+5)
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100x + 70*5 = 90x + 90*5
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10x = 20*5
x = 10 gallons (amt. of 100% acid to add)
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Cheers,
Stan H.