document.write( "Question 25177: An automobile cooling system currently has 20 quarts of a 35% antifreeze solution. The manufacturer recommends the systme be filled with a 50% antifreeze solution. How much of the 35% soulution must be drained off so that when replaced by pure antifreeze, the system contains the recommended 50% solution? \n" ); document.write( "
Algebra.Com's Answer #13506 by AnlytcPhil(1806)\"\" \"About 
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An automobile cooling system currently has 20 quarts of a 35% antifreeze\r\n" );
document.write( "solution.  The manufacturer recommends the systme be filled with a 50%\r\n" );
document.write( "antifreeze solution.  How much of the 35% soulution must be drained off so\r\n" );
document.write( "that when replaced by pure antifreeze, the system contains the recommended 50%\r\n" );
document.write( "solution?\r\n" );
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document.write( "Let x = amount to be drained off\r\n" );
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document.write( "After we drain off x quarts we have left 20-x quarts of 35% solution.\r\n" );
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document.write( "The number of quarts of pure antifreeze contained in the 20-x quarts that are\r\n" );
document.write( "left in the radiator after draining is .35(20-x)\r\n" );
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document.write( "The number of quarts of pure antifreeze contained in the x quarts that we are\r\n" );
document.write( "going to add is x quarts, because it is 100% antifreeze\r\n" );
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document.write( "The total number of quarts of pure antifreeze contained in the full radiator\r\n" );
document.write( "after we add the x quarts of pure antifreeze is\r\n" );
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document.write( ".35(20-x) + x\r\n" );
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document.write( "Also the number of quarts of pure antifreeze that must be contained in the\r\n" );
document.write( "full radiator after we add the pure antifreeze must be 50% of 20 or .50(20)\r\n" );
document.write( "or 10 quarts\r\n" );
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document.write( "So .35(20-x) + x must equal 10\r\n" );
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document.write( ".35(20-x) + x = 10 \r\n" );
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document.write( "solve that and get x = 60/13 or 4 8/13 quarts\r\n" );
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document.write( "Edwin \r\n" );
document.write( "AnlytcPhil@aol.com
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