document.write( "Question 1077372: How long will it take to double your money if you invest it at a rate of 8% compounded annually?
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Algebra.Com's Answer #691836 by math_helper(2461) $\"\"$ $\"About$

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$\"F+=+P%281%2Br%2Fn%29%5E%28nt%29+\"$ \r
\n" ); document.write( "\n" ); document.write( "n = number of payments per year
\n" ); document.write( "r = interest rate per year, expressed as a decimal
\n" ); document.write( "P = present value
\n" ); document.write( "F = future value
\n" ); document.write( "t = time, in units of years\r
\n" ); document.write( "\n" ); document.write( "This problem has: t=unknown, F=2P, r=0.08, n=1\r
\n" ); document.write( "\n" ); document.write( " $\"F+=+2P+=+P%281%2B0.08%29%5E%28t%29+\"$
\n" ); document.write( " $\"+++++2+=+%281.08%29%5Et+\"$
\n" ); document.write( " $\"++ln%282%29+=+t%2Aln%281.08%29+\"$ <— key step, take ln() of both sides, $\"+ln%28a%5Eb%29+=+b%2Aln%28a%29+\"$
\n" ); document.write( " $\"+++ln%282%29%2Fln%281.08%29+=+t+\"$
\n" ); document.write( " $\"+++highlight%28t+=+9.00years%29+\"$ \n" ); document.write( "

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