document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=515124>Question 515124</A>: <I><SPAN STYLE=\"word-break: break-all;\"> David invests $2,000 at 8% interest. About how long will it take for him to double his investment? (e.g, to $4,000)?<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 #343744 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=343744\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> David invests $2,000 at 8% interest. About how long will it take for him to double his investment?David invests $2,000 at 8% compound interest. <BR>\n" );
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document.write( "A(t) = P(1+(r/n))^(nt)<BR>\n" );
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document.write( "4000 = 2000(1+ 0.08/1))^(1*t)<BR>\n" );
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document.write( "(1+0.08)^t = 2<BR>\n" );
document.write( "t*log(1.08) = log(2)<BR>\n" );
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document.write( "time = log(2)/log(1.08) = 9 years<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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