document.write( "Question 341600: A health clinic uses a solution of bleach to sterilize petri dishes in which cultures are grown. The sterilization tank contains 80 gal of a solution of 4% ordinary household bleach mixed with pure distilled water. New research indicates that the concentration of bleach should be 7% for complete sterilization. How much of the solution should be drained and replaced with bleach to increase the bleach content to the recommended level? \n" ); document.write( "
Algebra.Com's Answer #244705 by ankor@dixie-net.com(22740)\"\" \"About 
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The sterilization tank contains 80 gal of a solution of 4% ordinary household
\n" ); document.write( " bleach mixed with pure distilled water.
\n" ); document.write( " New research indicates that the concentration of bleach should be 7% for
\n" ); document.write( " complete sterilization.
\n" ); document.write( " How much of the solution should be drained and replaced with bleach to increase
\n" ); document.write( " the bleach content to the recommended level?
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\n" ); document.write( "Let x = amt of original solution removed and amt of pure bleach to be added
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\n" ); document.write( "Amt of bleach equation:
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\n" ); document.write( ".04(80 - x) + x = .07(80)
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\n" ); document.write( "3.2 - .04x + x = 5.6
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\n" ); document.write( "-.04x + 1x = 5.6 - 3.2
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\n" ); document.write( ".96x = 2.4
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\n" ); document.write( "x = \"2.4%2F.96\"
\n" ); document.write( "x = 2.5 gal removed and 2.5 gal of bleach added
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\n" ); document.write( "Check solution in original equation
\n" ); document.write( ".04(80 - 2.5) + 2.5 = .07(80)
\n" ); document.write( ".04(77.5) + 2.5 = 5.6
\n" ); document.write( "3.1 + 2.5 = 5.6 \n" ); document.write( "
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