document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=589070>Question 589070</A>: <I><SPAN STYLE=\"word-break: break-all;\"> how long will it take to quadruple your money if you invest it at an interest rate of 5% and it is compounded every 4 months? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #374725 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><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=374725\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> how long will it take to quadruple your money if you invest it at an interest rate of 5% and it is compounded every 4 months?<BR>\n" );
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document.write( "compound interest formula: A=P(1+r)^n, P=initial investment, r=interest rate per period, n=number of periods, A=amount after n periods<BR>\n" );
document.write( "A/P=(1+r)^n=4<BR>\n" );
document.write( "For given problem:<BR>\n" );
document.write( "3 compound periods per year<BR>\n" );
document.write( "r=.05/3<BR>\n" );
document.write( "n=number of compound periods (what we want to find)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "(1+r)^n=4<BR>\n" );
document.write( "(1+.05/3)^n=4<BR>\n" );
document.write( "take log of both sides<BR>\n" );
document.write( "nlog(1+.05/3)=log(4)<BR>\n" );
document.write( "n=log(4)/log(1+.05/3)<BR>\n" );
document.write( "using calculator<BR>\n" );
document.write( "n&#8776;84 compound periods<BR>\n" );
document.write( "or<BR>\n" );
document.write( "84/3&#8776;28 yrs\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );