document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=998304>Question 998304</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A goldsmith needs 120 grams of gold alloy, of 75% pure gold. Only two alloys of gold are available, the first being 80% pure gold and the other 60% pure gold. How many grams of 80% pure gold must he use to suit his requirements?<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #616107 by </B><A HREF=/tutors/aboutme.mpl?userid=addingup><B>addingup(3677)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=addingup><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/cgi-bin/show-face.mpl?user=addingup><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=616107\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> mix .80 and .60 to get 120 at .75 <BR>\n" );
document.write( "x+y= 120 Subtract y from both sides:<BR>\n" );
document.write( "x= 120-y We'll use this value for x in the formula below:<BR>\n" );
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document.write( ".80x+.60y= .75(120) Substitute for x:<BR>\n" );
document.write( ".80(120-y)+.60y= .75(120) Let's multiply to get rid of parenthesis:<BR>\n" );
document.write( "96-.80y+60y= 90 Subtract 96 on both sides:<BR>\n" );
document.write( "-.80y+60y= -6 Add on left:<BR>\n" );
document.write( "-.20y= -6 Divide both sides by -.20:<BR>\n" );
document.write( "y= -6/-.20 When you divide, remember that - and - = +<BR>\n" );
document.write( "y= 30 grams will be at 60% and<BR>\n" );
document.write( "120-30= 90 grams will be at 80%\r<BR>\n" );
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