document.write( "Question 1162508: what rate of interest compounded annually is required to triple an investment in 22 years? \n" ); document.write( "

Algebra.Com's Answer #786304 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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what rate of interest compounded annually is required to triple an investment in 22 years?
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\n" ); document.write( "let r = interest rate in decimal form
\n" ); document.write( "let original investment = 1, the resulting amt = 3
\n" ); document.write( " $\"1%2A%281%2Br%29%5E22\"$ = 3
\n" ); document.write( "using common logs
\n" ); document.write( " $\"log%28%281%2Br%29%5E22%29+=+log%283%29\"$
\n" ); document.write( "log equiv of exponents
\n" ); document.write( "22*log(1+r) = log(3)
\n" ); document.write( "22*log(1+r) = .477
\n" ); document.write( "log(1+r) = $\".477%2F22\"$
\n" ); document.write( "log(1+r) = .0217
\n" ); document.write( "Antilog
\n" ); document.write( "1 + r = 1.0512
\n" ); document.write( "r = 1.0512 - 1
\n" ); document.write( "r = .0512 which is 5.12 %
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\n" ); document.write( "Check on your calc: enter 1.0512^22 = 2.9997 ~ 3 \n" ); document.write( "

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