document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=367156>Question 367156</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Where do I start? <BR>\n" );
document.write( "OLD COINS: A salesperson used her $3,500 year-end bonus to purchase some old coins, with hopes of earning 15% annual interest on the gold coins and 12% annual interest on the silver coins. If she saw return on her investment of $480 the first year, how much did she invest in each type of coin? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #261772 by </B><A HREF=/tutors/aboutme.mpl?userid=Earlsdon><B>Earlsdon(6294)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Earlsdon><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=261772\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> You can start by assigning variables to the unknown quantities, the invested amounts in gold and in silver.<BR>\n" );
document.write( "Let G = the number of dollars invested in gold and S = the number of dollars invested in silver.<BR>\n" );
document.write( "The sum of these two amounts is given as $3,500.00, so you can write:<BR>\n" );
document.write( "1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=G%2BS+=+3500 ALIGN=MIDDLE  ALT=\"G%2BS+=+3500\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Now we must find an equation for the amount of interest earned.<BR>\n" );
document.write( "The interest earned on the gold investment is 15%(G) and the interest earned on the silver investment is 12%(S), and the sum of these two amounts is given as $480.00<BR>\n" );
document.write( "So, after changing the percents to their decimal equivalents, you can write the equation:<BR>\n" );
document.write( "2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.15G%2B0.12S+=+480 ALIGN=MIDDLE  ALT=\"0.15G%2B0.12S+=+480\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Now let's replace the G in equation 2) with its equivalent: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=G+=+3500-S ALIGN=MIDDLE  ALT=\"G+=+3500-S\"   DISABLED_style= \"max-width:90%; height:auto;\" > which we get from equation 1) by solving for G.<BR>\n" );
document.write( "3) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.15%283500-S%29%2B0.12S+=+480 ALIGN=MIDDLE  ALT=\"0.15%283500-S%29%2B0.12S+=+480\"   DISABLED_style= \"max-width:90%; height:auto;\" > Simplify and solve for S.<BR>\n" );
document.write( "3a) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=525-0.15S%2B0.12S+=+480 ALIGN=MIDDLE  ALT=\"525-0.15S%2B0.12S+=+480\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "3b) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=525-0.03S+=+480 ALIGN=MIDDLE  ALT=\"525-0.03S+=+480\"   DISABLED_style= \"max-width:90%; height:auto;\" > Subtract 525 from both sides.<BR>\n" );
document.write( "3c) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-0.03S+=+-+45 ALIGN=MIDDLE  ALT=\"-0.03S+=+-+45\"   DISABLED_style= \"max-width:90%; height:auto;\" > Finally, divide both sides by -0.03<BR>\n" );
document.write( "3d) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28S+=+1500%29 ALIGN=MIDDLE  ALT=\"highlight%28S+=+1500%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > This is the number of dollars invested in silver.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=G+=+3500-S ALIGN=MIDDLE  ALT=\"G+=+3500-S\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=G+=+3500-1500 ALIGN=MIDDLE  ALT=\"G+=+3500-1500\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight_green%28G+=+2000%29 ALIGN=MIDDLE  ALT=\"highlight_green%28G+=+2000%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > and this is the number of dollars invested in gold.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );