document.write( "Question 1119385: I tried looking at some examples but i'm still confused. Can someone help please? thank you. \r
\n" ); document.write( "\n" ); document.write( "A chemical company makes two brands of antifreeze. The first brand is 20% pure antifreeze and the second brand is 70% pure antifreeze. In order to obtain 180 gallons of a mixture that contains 40% pure antifreeze, how many gallons of each brand of antifreeze must be used?
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Algebra.Com's Answer #734920 by ikleyn(52781)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Let x = \"how many gallons of the 70% brand to use\", in gallons.\r\n" );
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document.write( "Then the volume of the 20% brand must be (180-x) gallons.\r\n" );
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document.write( "The balance equation for the PURE antifreeze is THIS\r\n" );
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document.write( "    0.2*(180-x) + 0.7*x = 0.4*180.        <<<---=== It is the key equation\r\n" );
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document.write( "Simplify and solve for x:\r\n" );
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document.write( "    36 - 0.2x + 0.7x = 72\r\n" );
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document.write( "    0.5x = 72 - 36 = 36.\r\n" );
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document.write( "    x = \"36%2F0.5\" = 72.\r\n" );
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document.write( "Answer.  72 gallons of 70% brand  and  (180-72) = 108 gallons of 20% brand.\r\n" );
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document.write( "Check.   0.7*72 + 0.2*108 = 72 gallons of pure antifreeze.\r\n" );
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document.write( "         0.4*180 = 72 gallons of pure antifreeze.    ! Correct !\r\n" );
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\n" ); document.write( "\n" ); document.write( "Introductory lessons in this site,  covering various types of mixture problems,  are\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
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\n" ); document.write( "\n" ); document.write( "Read them and become an expert in solution the mixture word problems.\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 online textbook 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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