Question 432116
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*[tex \LARGE \ \ \ \ \ \ \ \ \ \ A\ =\ P\left(1\ +\ \frac{r}{n}\right)^{nt}]


Where *[tex \Large A] is the future value, *[tex \Large P] is the present value, *[tex \Large r] is the annual interest rate as a decimal, *[tex \Large n] is the number of compounding periods per year, and *[tex \Large t] is the number of years.


For your situation, just plug in the given numbers:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ A\ =\ 620\left(1\ +\ \frac{0.04}{4}\right)^{4t}]


For the principal to to double, *[tex \Large A] has to be 2 times *[tex \Large P], hence


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \left(1\ +\ \frac{0.04}{4}\right)^{4t}\ =\ 2]


Just solve the exponential equation for *[tex \Large t]


John
*[tex \LARGE e^{i\pi} + 1 = 0]
My calculator said it, I believe it, that settles it
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