SOLUTION: Near Three Rivers, NM, there is an archaeological site containing petroglyphs. In 1998, archaeologists found that the amount of carbon-14 in the petroglyphs was 88.5%. Determine th

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: Near Three Rivers, NM, there is an archaeological site containing petroglyphs. In 1998, archaeologists found that the amount of carbon-14 in the petroglyphs was 88.5%. Determine th      Log On


   

Question 633093: Near Three Rivers, NM, there is an archaeological site containing petroglyphs. In 1998, archaeologists found that the amount of carbon-14 in the petroglyphs was 88.5%. Determine the approximate age of the petroglyphs. Show the carbon-14 dating model for the age of the petroglyphs and define variables. Explain how you found your answer. There are directions for how to type math characters in the Resource Center that will show you show to enter exponents and fractions.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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In 1998, archaeologists found that the amount of carbon-14 in the petroglyphs
was 88.5%.
Determine the approximate age of the petroglyphs.
Show the carbon-14 dating model for the age of the petroglyphs
:
Radio active decay formula
A = Ao(2^(-t/h), where:
A = remaining amt after t years
Ao = initial amt t=0
t = time in yrs
h = half-life of substance
t = time of decay
:
A = .885
Ao = 1
h = 5730, the half life of carbon-14
:
1*2^(-t/5730) = .885
using nat logs
-t%2F5730*ln(2) = ln(.885)
-t%2F5730 = ln%28.885%29%2Fln%282%29
-t%2F5730 = -.17625
t = -5730 * -.17625
t = 1010 years is the age of the petro-whatevers