00:01
So in this problem, we're told that moore is going to invest $3 ,000, and he's going to do this for 20 years, and he's going to get an annual interest rate of 1 .5%.
00:09
We want to know what would be the total amount at the very end.
00:13
Well, what we can do is we can set up our summation symbol, because essentially we're adding up all the years.
00:19
So here's our summation symbol.
00:21
We'll start with x is equal to 1, meaning we're starting with that first year.
00:24
And our upper limit will be 20 because he's going to do this for 20 years.
00:29
Now for our formula, our initial value is 3 ,000.
00:32
So that would be the first term in this series.
00:35
And then you almost have to think about, yes, he's earning 1 .5 % interest, but that's on top of the amount he already has there.
00:43
So really, you would take your 100 % that he has, plus you're getting an additional 1 .5%, which means it's really going to be 101 .5%.
00:52
So now to make that into decimal, we move our decimal point two places to the right.
00:55
So it would be 1 .015 being raised to the x minus 1 power.
01:01
Okay...