document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=955652>Question 955652</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose $20,000 is invested into an account where interest is compounded semiannually. After 30 years the balance is $231,165.\r<BR>\n" );
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document.write( "What was the interest rate as a percent?\r<BR>\n" );
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document.write( "Round the answer to the nearest hundredth of a percent.<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 #583827 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=583827\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Suppose $20,000 is invested into an account where interest is compounded semiannually. After 30 years the balance is $231,165. <BR>\n" );
document.write( "What was the interest rate as a percent? <BR>\n" );
document.write( "Round the answer to the nearest hundredth of a percent.<BR>\n" );
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document.write( "Compound  Interest Formula: A=P(1+r/n)^nt, P=initial investment, r=interest rate, n=number of compounding periods per year, A=amt after t-years<BR>\n" );
document.write( "For given problem:<BR>\n" );
document.write( "P=20000<BR>\n" );
document.write( "r=interest rate(to be determined)<BR>\n" );
document.write( "n=2<BR>\n" );
document.write( "t=30<BR>\n" );
document.write( "A=amt after 30 yrs<BR>\n" );
document.write( "...<BR>\n" );
document.write( "231165=20000(1+r/2)^2*30<BR>\n" );
document.write( "231165/20000=(1+r/2)^60<BR>\n" );
document.write( "11.5583=(1+r/2)^60<BR>\n" );
document.write( "raise both sides to the 1/60th power<BR>\n" );
document.write( "1.04163=1+r/2<BR>\n" );
document.write( "r/2=1.04163-1=.04163<BR>\n" );
document.write( "r=.02082=2.082%<BR>\n" );
document.write( "What was the interest rate as a percent?  2.082% </SPAN>\n" );
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