document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=211309>Question 211309</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0321296443/algebrahomeworkh>College Algebra</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> A goldsmith has 120 grams of a gold alloy (a mixture of gold and one or more metals) containing 75% pure gold. How much pure gold must be added to this alloy to make it 80% pure gold? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #159656 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=159656\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A goldsmith has 120 grams of a gold alloy (a mixture of gold and one or more metals) containing 75% pure gold. How much pure gold must be added to this alloy to make it 80% pure gold?<BR>\n" );
document.write( "-------------------------------------------<BR>\n" );
document.write( "Equation:<BR>\n" );
document.write( "gold + gold = gold<BR>\n" );
document.write( "0.75*120 + x = 0.80(120+x)<BR>\n" );
document.write( "Multiply thru by 100 to get:<BR>\n" );
document.write( "75*120 + 100x = 80*120 + 80x<BR>\n" );
document.write( "20x = 5*120<BR>\n" );
document.write( "x = 30 grams (amt. of pure gold that must be added)<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );