00:02
A equals p times 1 plus r to write.
00:11
So then that is 9 ,000 equals p1 plus 0 .125 to the 1, right? so you can reorganize that to get p equals 9 ,000 which gives you 8 ,000, okay? sorry, that was it, that's supposed to be a.
00:43
Okay.
00:46
4 -8 -2, you have...
00:50
Okay, so then that is 2 times 2 ,250, 2 ,250 times 1 plus 0 .0 .087.
01:23
4 to the 4a t okay so then that is 2 equals 1 plus 0 .0 .087 5 044 to the 4 t okay then you take the ln of both sides okay and because you did that you can pull 4 at t to the front so then ln of two equals 4 t l n of 1 plus 0 .0 875 over 4 and t equals l n of 2 over 4 ln of 1 plus 0 .0 875 over 4 which is approximately 8 .0 .0 years.
02:39
Now for three, let's start with the basic equation we use with these sorts of problems.
02:47
Alright, so then the time to double is what, 20 years, right? so we can use that to find the weight, you know, the doubling way, okay? so then 2 equals e to the 20 r...