SOLUTION: An artifact was found and tested for its carbon-14 content. If 82% of the original carbon-14 was still present, what is its probable age (to the nearest 100 years)? (Carbon-14 has

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Question 849361: An artifact was found and tested for its carbon-14 content. If 82% of the original carbon-14 was still present, what is its probable age (to the nearest 100 years)? (Carbon-14 has a half-life of 5,730 years.)
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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An artifact was found and tested for its carbon-14 content.\
If 82% of the original carbon-14 was still present, what is its probable age (to the nearest 100 years)? (Carbon-14 has a half-life of 5,730 years.)
:
The radioactive decay formula: A = Ao*2^(-t/h) where:
A = amt remaining after t time
Ao = initial amt (t=0)
t = time of decay
h = half-life of substance
:
Let Ao = 1 then A = .82
2^(-t/5730) = .82
using common logs
-t%2F5730log(2) = log(.83)
-t%2F5730 = log%28.83%29%2Flog%282%29
-t%2F5730 = -.2863
t = -5730 * -.2863
t = 1640 ~ 1600 yrs