Question 1166448
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Continuous compound interest formula:<br>
{{{A = Pe^(rt)}}}<br>
t (years) is the unknown
r (interest rate) is 7% = .07
P is the principal, $11,000
A is the amount you want to have -- the $11,000 principal, plus $4,609.74 interest = $15,609.74<br>
{{{15609.74 = 11000e^(.07t)}}} [1]<br>
The unknown is in the exponent, so use logarithms.<br>
{{{15609.74/11000 = e^(.07t)}}}
{{{ln(15609.74/11000) = .07t}}}
{{{t = (ln(15609.74/11000))/.07}}}<br>
Use a calculator....<br>
Or solve the equation [1] with a graphing calculator by graphing the two expressions and find their point of intersection.<br>