Question 733352
<pre>
4000 = 1000e<sup>(.092)(t)</sup>

Divide both sides by 1000

   4 = e<sup>(.092t)</sup>

Use the definition of a natural logarithm which is:

A = e<sup>C</sup> is equivalent to the equation C = ln(A)
where A = 4 and C = .092t

   ,092t = ln(4)

       t = {{{ln(4)/.092}}}

       t = 15.06841697 years or about 15 years

Edwin</pre>