document.write( "Question 416428: How much pure acid should be mixed with 2 gallons of a 40% acid solution in order to get an 80%acid solution
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Algebra.Com's Answer #291754 by stanbon(75887)\"\" \"About 
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How much pure acid should be mixed with 2 gallons of a 40% acid solution in order to get an 80% acid solution
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\n" ); document.write( "Equation:
\n" ); document.write( "acid + acid = acid
\n" ); document.write( "0.40*2 + 1*x = 0.80(2+x)
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\n" ); document.write( "Multiply thru by 100 to get:
\n" ); document.write( "40*2 + 100x = 80*2 + 80x
\n" ); document.write( "20x = 40*2
\n" ); document.write( "x = 4 gallons (amt. of pure acid needed)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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