SOLUTION: I need some help in solving this problem step by step. I really don't understand it. The formula to be used is: P(t)= Poe-kt, k>o. The question states, "Archaeology soil from benea

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: I need some help in solving this problem step by step. I really don't understand it. The formula to be used is: P(t)= Poe-kt, k>o. The question states, "Archaeology soil from benea      Log On


   

Question 327422: I need some help in solving this problem step by step. I really don't understand it. The formula to be used is: P(t)= Poe-kt, k>o. The question states, "Archaeology soil from beneath the Kish Church in Azerbaijan was found to have lost 12% of its carbon-14. How old was the soil?" I would appreaciate it. Thanks you very much!
Answer by galactus(183) About Me  (Show Source):
You can put this solution on YOUR website!
There is not enough info given. You need the decay constant, k.
Fortunately, we know that the half-life of Carbon-14 is about 5750 years.
There is a formula for half-life, k=-ln(2)/T. In this case, T=5750.
This means k=-ln%282%29%2F5750=-.00012
If 12% is gone, then 88% remains.
So, we have:
.88P=Pe%5E%28-.00012t%29
The P's cancel and we have:
.88=e%5E%28-.00012t%29
ln%28.88%29=-.00012t
t=ln%28.88%29%2F-.00012=1065.28 years.