document.write( "Question 1124059: How much pure acid should be mixed with 7 gallons of a​ 50% acid solution in order to get an​ 80% acid​ solution? \n" ); document.write( "
Algebra.Com's Answer #740427 by ankor@dixie-net.com(22740)\"\" \"About 
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How much pure acid should be mixed with 7 gallons of a​ 50% acid solution in order to get an​ 80% acid​ solution?
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\n" ); document.write( "let x = amt of pure acid
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\n" ); document.write( "A typical mixture equation
\n" ); document.write( "x + .50(7) = .8(x+7)
\n" ); document.write( "x + 3.5 = .8x + 5.6
\n" ); document.write( "x - .8x = 5.6 - 3.5
\n" ); document.write( ".2x = 2.1
\n" ); document.write( "x = 2.1/.2
\n" ); document.write( "x = 10.5 gallons of pure acid required:
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\n" ); document.write( "confirm this in the original equation
\n" ); document.write( "10.5 + .5(7) = .8(10.5+7)
\n" ); document.write( "10.5 + 3.5 = .8(17.5) \n" ); document.write( "
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