Question 1163089
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The formula for continuous compounding is<br>
{{{A = Pe^(rt)}}}<br>
P is the beginning principal
A is the final amount
r is the annual interest rate
t is the number of years<br>
You know the interest rate; and you know you want the amount to double -- that is, you want A = 2P.  So<br>
{{{2P = Pe^(rt)}}}
{{{e^(rt) = 2}}}
{{{rt = ln(2)}}}
{{{t = ln(2)/r}}}<br>
Substitute the given interest rate of 20% (0.20) and use a calculator.<br>
Note that the original amount is irrelevant; for a given interest rate, the doubling time is the same whether the original amount is a dollar or a million dollars.<br>