http://www.pblpathways.com/projects/potassium_dating/potassium_dating.pdf
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The equation and method are given to you.
y = y0 e^(-kt).
"k is found using the half-life of potassium 40".
You are told the half life. Plug that in for t. Set e^(-kt) = 1/2. Solve for k.
Then you are told values for y and y0. (That is, you are told what y, the amount potassium-40 is now. And you are told how much Argon-40 there is now and that was originally potassium-40. So you know how much total potassium-40 there was, y0).
So since you know y, y0 and k, you plug them in to solve for t.
y = y0 e^(-kt).
"k is found using the half-life of potassium 40".
You are told the half life. Plug that in for t. Set e^(-kt) = 1/2. Solve for k.
Then you are told values for y and y0. (That is, you are told what y, the amount potassium-40 is now. And you are told how much Argon-40 there is now and that was originally potassium-40. So you know how much total potassium-40 there was, y0).
So since you know y, y0 and k, you plug them in to solve for t.
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please go
http://www.pblpathways.com/projects/pota…
http://www.pblpathways.com/projects/pota…