The radioactive carbon-14 in an organism at the time of its death decays according to the equation
where t is time in years and A_0 is the amount of carbon-14 present at time t=0. Estimate the age of a skull uncovered in an archaeological site if 10% of the original amount of carbon-14 is still present. [Hint: Find t such that A=0.1*A_0.]
This shows how to work with a carbon dating word problem.