Question 1139014
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<pre>
Let "n" be the number of quarter periods.


12400 = {{{8000*(1+0.07/4)*n}}},


{{{12400/8000}}} = {{{(1+0.07/4)^n}}}


1.55 = {{{(1+0.07/4)^n}}}


log(1.55) = n*log(1+0.07/4)


n = {{{log(1.55)/log((1+0.07/4))}}} = 25.26 quarter periods.


<U>ANSWER</U>.  6 years and half of on year is enough.


<U>CHECK</U>.  {{{8000*(1+0.07/4)*26}}} = 12.559.86 dollars.
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Solved.