00:01
If the interest on an account is 11 .5 % compounded yearly, how long will it take to triple that amount? well, we need to assume our principle.
00:11
So our principle, we'll just keep it easy, make it a dollar.
00:14
So to triple that, we need to use the amount to be $3.
00:18
So when we use the formula, a equals p, 1 plus r over n to the nt, we're going to have 3 equals 1, 1, 1 plus my interest rate is 11 .5.
00:29
So we'll go .115 over we have a compounded yearly one and that would be to the t power.
00:38
So that's going to be three equals 1 .15, 1 .115 to the t power.
00:46
So we need to take the natural log of both sides and that'll make that t natural log of 1 .115 and then we divide by a natural log of 1 .1 .15 and we'll have a natural log of 1 .115 and we'll have have our answer for t.
01:03
So i'm going to natural log of three, divide that by natural log of 1 .115, and i'm going to get 10 .09 years...