document.write( "Question 220267: how many years would it take to double $100 if it earned interest at a rate of 8% per year? \n" ); document.write( "

Algebra.Com's Answer #165410 by Theo(13342) $\"\"$ $\"About$

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$\"100%2A%281.08%29%5Ex+=+200\"$
\n" ); document.write( " $\"log%28%28100%2A1.08%29%5Ex%29+=+log%28%28200%29%29\"$
\n" ); document.write( "This becomes:
\n" ); document.write( " $\"log%28%28100%29%29+%2B+x%2Alog%28%281.08%29%29+=+log%28%28200%29%29\"$
\n" ); document.write( "This becomes:
\n" ); document.write( " $\"x+=+%28log%28%28200%29%29+-+log%28%28100%29%29%29%2Flog%28%281.08%29%29\"$
\n" ); document.write( "This becomes:
\n" ); document.write( "x = 9.006468342
\n" ); document.write( "-----
\n" ); document.write( "to prove this is true, substitute in original equation to get:
\n" ); document.write( " $\"100%2A%281.08%29%5E9.006468342+=+200\"$
\n" ); document.write( "This becomes:
\n" ); document.write( "200 = 200 confirming the answer of x = 9.006468342 is good.
\n" ); document.write( "-----
\n" ); document.write( "It would take 9.006468342 years to double your money at 8% compounded yearly.
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