document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=531021>Question 531021</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I'm trying to figure out the formula for this word problem.  If I can figure out the formula for mixtures I should be able to do the entire worksheet.\r<BR>\n" );
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document.write( "Sample Problem:  A Chemist has a solution that is 12% acid and another solution that is 42% acid. She wants 10L of solution that is 30% acid.  How much of each solution should she mix? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #350306 by </B><A HREF=/tutors/aboutme.mpl?userid=oberobic><B>oberobic(2304)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=oberobic><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=350306\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> With solution problems you need to determine how much 'pure' stuff you have or need.<BR>\n" );
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document.write( "The chemist needs 10 liters of a 30% acid.  .3*10 = 3 liters of 'pure' acid in a solvent (likely water).<BR>\n" );
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document.write( "She has 12% acid and 42% acid to mix together.<BR>\n" );
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document.write( "x = liters of 12% acid<BR>\n" );
document.write( "y = liters of 42% acid<BR>\n" );
document.write( "x+y =10<BR>\n" );
document.write( "so<BR>\n" );
document.write( "x = 10-y<BR>\n" );
document.write( "or<BR>\n" );
document.write( "y = 10 - x <BR>\n" );
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document.write( ".12*x + .42*y = .3*10<BR>\n" );
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document.write( "multiply by 100 to eliminate decimals<BR>\n" );
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document.write( "12x + 42y = 30*10<BR>\n" );
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document.write( "substitute for x<BR>\n" );
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document.write( "12(10-y) + 42y = 300<BR>\n" );
document.write( "120 -12y + 42y = 300<BR>\n" );
document.write( "30y = 180<BR>\n" );
document.write( "y = 6 <BR>\n" );
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document.write( "Answer: Mix 6 liters of 42% acid and 4 liters of 12% acid.<BR>\n" );
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document.write( "Check the amount of pure acid to be sure this answer is correct.<BR>\n" );
document.write( ".42*6 = 2.52<BR>\n" );
document.write( ".12*4 = 0.48<BR>\n" );
document.write( "2.52 + .48 = 3.0<BR>\n" );
document.write( "Correct.<BR>\n" );
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document.write( "Done. </SPAN>\n" );
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