Use guess and check to find how many years it will take for your money to double if you have 2,000 invested with a growth rate of 7% per year, rounded up to the nearest year.

Question

yusmin · Answer

The money will double after how many years?

dumbcow · Answer

If we are just estimating then there is a quick rule to use.
Divide rate into 72 to get num of years it takes to double your initial capital.

---> 72/7 = 10.3

So about 10 years

yusmin · Answer

ohhhh hmm yeah I have no idea what I was doing I got something totally off lol

dumbcow · Answer

For more exact answer, solve following equation
$$1.07^n = 2$$
$$n = \frac{\ln 2}{\ln 1.07}$$

yusmin · Answer

thank you so much

photon336 · Answer

$$[A_{0}]*(1.07)^{n} = 2[A_{0}]$$

and then solve for n