00:01
The thought process was coming up with a half -life problem, at least the way i like to do this, is the initial amount, which i like to do a -substrip 0, times the 1 -half to the t over k power, where k is a half -life.
00:17
So in this problem, again, i'm going to still use a.
00:22
So the amount over time is going to be, we start with 1 ,200 grams, 1 -half to the t over -hams.
00:32
They tell you in the problem is 5 ,700 is your half -life.
00:37
So that would be my answer to part a.
00:40
So then in part b, what you're supposed to do is take that same equation.
00:46
So now i'm ready for part b, 1 ,200 times your half to the t over 5 ,700.
00:54
And i want to tell you the time it takes to get down to 800 grams remaining.
01:00
So really it's just a few steps, like you want to divide the 1 ,200 over, and feel free to reduce as much as you want.
01:09
It's basically 8 over 12.
01:12
I'll just believe that's 8 over 12 right now, but both those numbers are divisible by 4, so it is 2 over 3...