doubling investments: finding time, given rate, compoundings

[icup]

How quickly will money double if it is invested
at an annual rate of 2% compounded 3 times per year?

formula I'm using: B(t)=P(1+r/k)^kt

Also, since I am doubling the investment the final formula I will use looks like this:

(1+.02/3)^3t=2

I am having trouble figuring out the most important step..... Solving for t. What do i need to do with ^3t

thank you

 

[stapel]

What do i need to do with ^3t

Take the log of either side, and move the "3t" from being a power inside the log to being a multiplier outside the log.

Then divide through by the "3" and the "ln(1 + 0.02/3)" to get the "exact" form of the answer. (Since this is a word problem asking for "time", the final answer should probably be expressed in decimal-approximation form.)

If you get stuck, please reply showing all of your work and reasoning. Thank you!

Eliz.