document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=457955>Question 457955</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Urgent help please!  How long will it take $900 to double itself if it is invested at 10% interest compounded semiannually? (Express the answer to the nearest tenth.)<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 #314120 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><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=314120\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Note: 900 doubles to 1800\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A=P%281%2Br%2Fn%29%5E%28n%2At%29 ALIGN=MIDDLE  ALT=\"A=P%281%2Br%2Fn%29%5E%28n%2At%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Start with the compound interest formula\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1800=900%281%2B0.10%2F2%29%5E%282%2At%29 ALIGN=MIDDLE  ALT=\"1800=900%281%2B0.10%2F2%29%5E%282%2At%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Plug in <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A=1800 ALIGN=MIDDLE  ALT=\"A=1800\"   DISABLED_style= \"max-width:90%; height:auto;\" >, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P=900 ALIGN=MIDDLE  ALT=\"P=900\"   DISABLED_style= \"max-width:90%; height:auto;\" >, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=0.10 ALIGN=MIDDLE  ALT=\"r=0.10\"   DISABLED_style= \"max-width:90%; height:auto;\" > (the decimal equivalent of 10%), and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n=2 ALIGN=MIDDLE  ALT=\"n=2\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1800=900%281%2B0.05%29%5E%282%2At%29 ALIGN=MIDDLE  ALT=\"1800=900%281%2B0.05%29%5E%282%2At%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Evaluate <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.10%2F2 ALIGN=MIDDLE  ALT=\"0.10%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" > to get <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.05 ALIGN=MIDDLE  ALT=\"0.05\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1800=900%281.05%29%5E%282%2At%29 ALIGN=MIDDLE  ALT=\"1800=900%281.05%29%5E%282%2At%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Add <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1 ALIGN=MIDDLE  ALT=\"1\"   DISABLED_style= \"max-width:90%; height:auto;\" > to <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.05 ALIGN=MIDDLE  ALT=\"0.05\"   DISABLED_style= \"max-width:90%; height:auto;\" > to get <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1.05 ALIGN=MIDDLE  ALT=\"1.05\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1800%2F900=%281.05%29%5E%282%2At%29 ALIGN=MIDDLE  ALT=\"1800%2F900=%281.05%29%5E%282%2At%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Divide both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=900 ALIGN=MIDDLE  ALT=\"900\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2=%281.05%29%5E%282%2At%29 ALIGN=MIDDLE  ALT=\"2=%281.05%29%5E%282%2At%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Evaluate <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1800%2F900 ALIGN=MIDDLE  ALT=\"1800%2F900\"   DISABLED_style= \"max-width:90%; height:auto;\" > to get <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2 ALIGN=MIDDLE  ALT=\"2\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%282%29=ln%28%281.05%29%5E%282%2At%29%29 ALIGN=MIDDLE  ALT=\"ln%282%29=ln%28%281.05%29%5E%282%2At%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Take the natural log of both sides.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%282%29=2%2At%2Aln%281.05%29 ALIGN=MIDDLE  ALT=\"ln%282%29=2%2At%2Aln%281.05%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Pull down the exponent using the identity  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=log%28b%2C%28x%5Ey%29%29=y%2Alog%28b%2C%28x%29%29 ALIGN=MIDDLE  ALT=\"log%28b%2C%28x%5Ey%29%29=y%2Alog%28b%2C%28x%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%282%29%2Fln%281.05%29=2%2At ALIGN=MIDDLE  ALT=\"ln%282%29%2Fln%281.05%29=2%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" > Divide both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ln%281.05%29 ALIGN=MIDDLE  ALT=\"ln%281.05%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.693147180559945%2Fln%281.05%29=2%2At ALIGN=MIDDLE  ALT=\"0.693147180559945%2Fln%281.05%29=2%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" > Evaluate the natural log of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2 ALIGN=MIDDLE  ALT=\"2\"   DISABLED_style= \"max-width:90%; height:auto;\" > to get <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.693147180559945 ALIGN=MIDDLE  ALT=\"0.693147180559945\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.693147180559945%2F0.048790164169432=2%2At ALIGN=MIDDLE  ALT=\"0.693147180559945%2F0.048790164169432=2%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" > Evaluate the natural log of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1.05 ALIGN=MIDDLE  ALT=\"1.05\"   DISABLED_style= \"max-width:90%; height:auto;\" > to get <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0.048790164169432 ALIGN=MIDDLE  ALT=\"0.048790164169432\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=14.2066990828905=2%2At ALIGN=MIDDLE  ALT=\"14.2066990828905=2%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" > Divide.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=14.2066990828905%2F2=t ALIGN=MIDDLE  ALT=\"14.2066990828905%2F2=t\"   DISABLED_style= \"max-width:90%; height:auto;\" > Divide both sides by 2 to isolate \"t\".\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=7.10334954144523=t ALIGN=MIDDLE  ALT=\"7.10334954144523=t\"   DISABLED_style= \"max-width:90%; height:auto;\" > Divide.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t=7.10334954144523 ALIGN=MIDDLE  ALT=\"t=7.10334954144523\"   DISABLED_style= \"max-width:90%; height:auto;\" > Rearrange the equation.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t=7.1 ALIGN=MIDDLE  ALT=\"t=7.1\"   DISABLED_style= \"max-width:90%; height:auto;\" > Round to the nearest tenth (ie to the nearest tenth of a year).\r<BR>\n" );
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document.write( "Answer: 7.1 years.<BR>\n" );
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