document.write( "Question 1100319: The car radiator holds 20L. It contains a 25% antifreeze solution. Since the weather is getting colder,
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Algebra.Com's Answer #714796 by ikleyn(52860) $\"\"$ $\"About$

You can put this solution on YOUR website!
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\n" ); document.write( "The car radiator holds 20L. It contains a 25% antifreeze solution. Since the weather is getting colder,
\n" ); document.write( "the mechanic should make the solution 40% antifreeze. How much of the 25% solution should be drained
\n" ); document.write( "and replaced with pure antifreeze to give a 40% solution.
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document.write( "Let V be the volume to drain off from 20 liters of antifreeze.\r\n" );
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document.write( "Step 1:  Draining.  After draining,  you have 20-V liters of the 25% antefreeze.\r\n" );
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document.write( "                    It contains 0.25*(20-V) of pure antifreeze.\r\n" );
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document.write( "Step 2:  Replacing.  Then you add V liters of the pure antifreeze (the replacing step).\r\n" );
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document.write( "                     After the replacing,  you have the same total liquid volume of 20 liters.\r\n" );
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document.write( "                     It contains 0.25(20-V) + V liters of pure antifreeze.\r\n" );
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document.write( "So, your \"concentration equation\" is\r\n" );
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document.write( " = 0.4.    (1)    <<<---=== It is the fraction of the pure antifreeze volume to the total volume.\r\n" );
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document.write( "The setup is done and completed.\r\n" );
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document.write( "To solve the equation (1), multiply both sides by 20. You will get\r\n" );
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document.write( "0.25*(20-V) + V= 0.4*20,\r\n" );
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document.write( "5 - 0.25V + V= 8,\r\n" );
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document.write( "0.75V = 8 - 5 = 3  ====>  V =  = 4 liters.\r\n" );
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document.write( "Answer.  4 liters of the 25% antifreeze must be drained and replace by 4 liters of pure antifreeze.\r\n" );
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document.write( "Check.    = 0.4.\r\n" );
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\n" ); document.write( "There is entire bunch of introductory lessons covering various types of mixture problems\r
\n" ); document.write( "\n" ); document.write( "    - Mixture problems\r
\n" ); document.write( "\n" ); document.write( "    - More Mixture problems\r
\n" ); document.write( "\n" ); document.write( "    - Solving typical word problems on mixtures for solutions \r
\n" ); document.write( "\n" ); document.write( "    - Word problems on mixtures for antifreeze solutions (*)\r
\n" ); document.write( "\n" ); document.write( "    - Word problems on mixtures for alloys \r
\n" ); document.write( "\n" ); document.write( "    - Typical word problems on mixtures from the archive\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
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\n" ); document.write( "\n" ); document.write( "Read them and become an expert in solution mixture word problems.
\n" ); document.write( "Notice that among these lessons there is one on antifreeze solutions marked by (*).\r
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\n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this textbook in the section \"Word problems\" under the topic \"Mixture problems\".\r
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\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
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\n" ); document.write( "Dear tutor @greenestamps !\r
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\n" ); document.write( "\n" ); document.write( "I sincerely ask you to change RADICALLY your tone regarding my solutions. \r
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\n" ); document.write( "\n" ); document.write( "What would be even better, if you stop to refer to my solutions at all,\r
\n" ); document.write( "\n" ); document.write( "except you see a direct error in it.\r
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\n" ); document.write( "\n" ); document.write( "Thanks,\r
\n" ); document.write( "\n" ); document.write( "Ikleyn.\r
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\n" ); document.write( "And notice, please, that I keep very neutral tone regarding your solutions even when I see them not fully completed or even incorrect.\r
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