document.write( "Question 189821: The radiator in a certain make of car needs to contain 30 liters of 40% antifreeze. The radiator now contains 30 liters of 20% antifreeze. How many liters of this solution must be drained and replaced with 100% antifreeeze to get the desired strength? \n" ); document.write( "
Algebra.Com's Answer #142416 by ankor@dixie-net.com(22740)\"\" \"About 
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The radiator in a certain make of car needs to contain 30 liters of 40%
\n" ); document.write( " antifreeze. The radiator now contains 30 liters of 20% antifreeze.
\n" ); document.write( " How many liters of this solution must be drained and replaced with 100%
\n" ); document.write( " antifreeze to get the desired strength?
\n" ); document.write( ":
\n" ); document.write( "Let x = amt of 20% solution to be drained, and also amt of 100% to be added
\n" ); document.write( ":
\n" ); document.write( ".2(30-x) + 1.0(x) = .4(30)
\n" ); document.write( "6 - .2x + 1x = 12
\n" ); document.write( "-.2x + 1x = 12 - 6
\n" ); document.write( ".8x = 6
\n" ); document.write( "x = \"6%2F.8\"
\n" ); document.write( "x = 7.5 liters to be removed and replaced
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\n" ); document.write( "Check solution in original equation
\n" ); document.write( ".2(30-7.5) + 7.5 = .4(30)
\n" ); document.write( ".2(22.5) + 7.5 = 12
\n" ); document.write( "4.5 + 7.5 = 12
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