document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=21050>Question 21050</A>: <I><SPAN STYLE=\"word-break: break-all;\"> This is from my 8th grade honors algebra... \r<BR>\n" );
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document.write( "Tori invested $24,000 , part at 8% and the rest at 7.2%.  How much did she invest at each rate if her income from the 8% investment is two-thirds of that of the 7.2% investment?\r<BR>\n" );
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document.write( "  I've made a chart...\r<BR>\n" );
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document.write( "       Amount invested   x    rate     =   interest income\r<BR>\n" );
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document.write( "              X      x         0.08    =       0.08X  =  y<BR>\n" );
document.write( "        ($24,000-X)     x        0.072      =    0.072($24,000-X)  = 2/3y\r<BR>\n" );
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document.write( "Then I'm totally stuck, we haven't solved with 2 unknowns yet! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #10137 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=10137\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Try this:<BR>\n" );
document.write( "Let x = the amount invested at 8% (0.08).<BR>\n" );
document.write( "The interest on this amount is written as: 0.08x<BR>\n" );
document.write( "Let (24000 - x) = the amount invested at 7.2% (0.072).<BR>\n" );
document.write( "The interest on this amount is written as: 0.072(24000 - x)\r<BR>\n" );
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document.write( "The interest on the 8% part is 2/3 the interest on the 7.2% part.<BR>\n" );
document.write( "So, you can say: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.08x+=+0.072%2824000-x%29%282%2F3%29 ALIGN=MIDDLE  ALT=\"0.08x+=+0.072%2824000-x%29%282%2F3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Now you can write the equation to solve this problem:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.08x+%2B+0.072%2824000+-+x%29+=+0.072%2824000+-+x%29+%2B+0.072%2824000+-+x%29%282%2F3%29 ALIGN=MIDDLE  ALT=\"0.08x+%2B+0.072%2824000+-+x%29+=+0.072%2824000+-+x%29+%2B+0.072%2824000+-+x%29%282%2F3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Simplify.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.08x+%2B+1728+-+0.072x+=+0.072%2824000+-+x%29%285%2F3%29 ALIGN=MIDDLE  ALT=\"0.08x+%2B+1728+-+0.072x+=+0.072%2824000+-+x%29%285%2F3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.008x+%2B+1728+=+%285%2F3%29%281728+-+0.072x%29 ALIGN=MIDDLE  ALT=\"0.008x+%2B+1728+=+%285%2F3%29%281728+-+0.072x%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.008x+%2B+1728+=+2880+-+0.12x ALIGN=MIDDLE  ALT=\"0.008x+%2B+1728+=+2880+-+0.12x\"   DISABLED_style= \"max-width:90%; height:auto;\" > Add 0.12x to both sides.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.128x+%2B+1728+=+2880 ALIGN=MIDDLE  ALT=\"0.128x+%2B+1728+=+2880\"   DISABLED_style= \"max-width:90%; height:auto;\" > Subtract 1728 from both sides.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.128x+=+1152 ALIGN=MIDDLE  ALT=\"0.128x+=+1152\"   DISABLED_style= \"max-width:90%; height:auto;\" > Finally, divide both sides by 0.128<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+9000 ALIGN=MIDDLE  ALT=\"x+=+9000\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "So, $9,000.00 was invested at 8% and ($24,000.00 - $9,000.00 = $15,000.00) was invested at 7.2%\r<BR>\n" );
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document.write( "Check:\r<BR>\n" );
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document.write( "0.08($9,000.00) = $720.00 The interest on the amount invested at 8%<BR>\n" );
document.write( "0.072($15,000.00) = $1,080.00 The interest on the amount invested at 7.2%.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%282%2F3%29%281080%29+=+720 ALIGN=MIDDLE  ALT=\"%282%2F3%29%281080%29+=+720\"   DISABLED_style= \"max-width:90%; height:auto;\" > Checks ok.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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