.72 = 1 (e^-.000124t
-.000124t ln e = ln .72
but lne =1
t = ln .72 /-.000124
= appr 2649 years
check my arithmetic
The age of a document is in dispute, so archaeologists test for carbon-14. Due to radioactive decay, the amount A of carbon -14 present compared to the initial amount A0 after t years is given by the formula A(t) = A0e^-0.000124t . If 72% of the original amount of carbon- 14 is present in the document, how old is it?
1 answer