document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1099037>Question 1099037</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If you put $1000 into a savings account that bears 1.5% interest per<BR>\n" );
document.write( "year, how long will it take that money to quadruple? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #713446 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=713446\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> quadruple is $4000<BR>\n" );
document.write( "4000=1000(1+.015)^n<BR>\n" );
document.write( "4=1.015^n<BR>\n" );
document.write( "ln4=n1n (1.015)<BR>\n" );
document.write( "n=93.1 years<BR>\n" );
document.write( "rule of 72: doubling time is 72/interest rate=48 years<BR>\n" );
document.write( "quadrupling is doubling of doubling, and that would be two doublings or 96 years, a good approximation. </SPAN>\n" );
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