document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1160813>Question 1160813</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A 4000 investment earns interest at 4%/ yr compunded quarterly. How long will it take to double the value of the investment. Please show me 4 steps </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #784211 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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/cgi-bin/show-face.mpl?user=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=784211\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 8000=4000(1+(.04/4))^4t, where t is number of years<BR>\n" );
document.write( "2=(1+0.01)^4t<BR>\n" );
document.write( "ln both sides<BR>\n" );
document.write( "ln 2=4t ln 1.01 rule of log<BR>\n" );
document.write( "t=ln2/(4 ln(1.01)<BR>\n" );
document.write( "=17.42 years\r<BR>\n" );
document.write( "\n" );
document.write( "Rule of 70<BR>\n" );
document.write( "70/rate in percent = time in years to double.<BR>\n" );
document.write( "Here, it would yield 70/4=17.5 years. </SPAN>\n" );
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