document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=624286>Question 624286</A>: <I><SPAN STYLE=\"word-break: break-all;\"> find the time when sum of $2400 increases by 1/5 of every year amounts to $3600.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Additional Details<BR>\n" );
document.write( "we need to know the rate of interest as given as per my opinion is the rate is 1/5 or what\r<BR>\n" );
document.write( "\n" );
document.write( "Thank you<BR>\n" );
document.write( "Joesph </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #392624 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=392624\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> find the time when sum of $2400 increases by 1/5 of every year amounts to $3600. <BR>\n" );
document.write( "**<BR>\n" );
document.write( "1/5 is the same as 20% interest so we can use the compound interest formula: <BR>\n" );
document.write( "A=P(1+i)^n, P=initial investment, i=interest rate per period, A=amount after n periods<BR>\n" );
document.write( "..<BR>\n" );
document.write( "For given problem:<BR>\n" );
document.write( "P=$2400<BR>\n" );
document.write( "i=20%<BR>\n" );
document.write( "n=to find<BR>\n" );
document.write( "A=$3600<BR>\n" );
document.write( "..<BR>\n" );
document.write( "3600=2400(1+.2)^n<BR>\n" );
document.write( "3600/2400=1.2^n<BR>\n" );
document.write( "1.5=1.2^n<BR>\n" );
document.write( "take log of both sides<BR>\n" );
document.write( "log1.5=nlog1.2<BR>\n" );
document.write( "n=log1.5/log1.2<BR>\n" );
document.write( "n&#8776;2.2 yrs<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );