document.write( "Question 1172281: An automobile radiator contains 18 quarts of a solution which is 20% alcohol and 80% water. How much of the solution
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Algebra.Com's Answer #797250 by ikleyn(52803) $\"\"$ $\"About$

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\n" ); document.write( "An automobile radiator contains 18 quarts of a solution which is 20% alcohol and 80% water. How much of the solution
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document.write( "Let V be the volume of the original solution to drain off from 18 quarts and to replace by pure alcohol.\r\n" );
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document.write( "Step 1:  Draining.  After draining,  you have 18-V quarts of the 20% solution.\r\n" );
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document.write( "                    It contains 0.20*(18-V) of pure alcohol.\r\n" );
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document.write( "Step 2:  Replacing.  Then you add V quarts of the pure alcohol (the replacing step).\r\n" );
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document.write( "                     After the replacing,  you have the same total liquid volume of 18 quarts.\r\n" );
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document.write( "                     It contains 0.20(18-V) + V quarts of the pure alcohol.\r\n" );
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document.write( "So, the alcohol concentration after replacement is  . \r\n" );
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document.write( "It is the ratio of the pure alcohol volume to the total volume.\r\n" );
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document.write( "Therefore, your \"concentration equation\" is\r\n" );
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document.write( "     = 0.3.    (1)    \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 18. You will get\r\n" );
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document.write( "    0.20*(18-V) + V= 0.3*18,\r\n" );
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document.write( "    3.6 - 0.20V + V = 5.4,\r\n" );
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document.write( "    0.8V = 5.4 - 3.6 = 1.8  ====>  V =  = 2.25 quarts.\r\n" );
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document.write( "Answer.  2.25 quarts of the 20% antifreeze must be drained and replaced by 2.25 quarts of the pure alcohol.\r\n" );
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document.write( "Check.    = 0.3.    ! Correct !\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
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\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( "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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