00:01
All right, you have two parts here.
00:03
The first part is to use the rule of 70 to estimate the doubling time, and that says to take 70 divided by r.
00:12
So the doubling time in years is approximately 70 divided by r, and we were given 2%, which is 35.
00:34
So 35 years is the estimate based on the rule of 70.
00:41
The actual doubling time.
00:44
We need to use our growth formula.
00:50
And in general, that looks like this.
00:56
We know that it's doubling so that we know if we started with 4 ,000, we want to end up with 8 ,000.
01:02
So that's going to look something like this.
01:04
8 ,000 is our end goal.
01:07
4 ,000 is what we started with.
01:11
And that rate is 2%...