document.write( "Question 219496: How long does it take your money in your savings account to double at 8% interest rate using the formula A=Pe^rt ? \n" ); document.write( "

Algebra.Com's Answer #165052 by josmiceli(19441) $\"\"$ $\"About$

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$\"A+=+Pe%5E%28rt%29\"$
\n" ); document.write( " $\"P\"$ is the original amount invested. The problem
\n" ); document.write( "wants to know how long (what $\"t\"$ is) it takes to
\n" ); document.write( "make $\"A\"$ twice this amount, so $\"A+=+2P\"$
\n" ); document.write( " $\"2P+=+Pe%5E%28rt%29\"$
\n" ); document.write( "given:
\n" ); document.write( " $\"r+=+.08\"$ (this is annual intest rate)
\n" ); document.write( " $\"2P+=+Pe%5E%28.08t%29\"$
\n" ); document.write( "Divide both sides by $\"P\"$
\n" ); document.write( " $\"2+=+e%5E%28.08t%29\"$
\n" ); document.write( "Take the natural log of both sides
\n" ); document.write( " $\"ln%282%29+=+.08t\"$
\n" ); document.write( " $\".69315+=+.08t\"$
\n" ); document.write( " $\"t+=+8.664\"$ ( $\"t\"$ is the time in years)
\n" ); document.write( "I can find $\".664\"$ years in months also
\n" ); document.write( " $\".664%2A12+=+7.9\"$ (about 8 months)
\n" ); document.write( "It takes 8 years and 8 months to double money\r
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