Question

A fossil is found to have a 14c level of 67.0% compared to living organisms. how old is the fossil?

Answer 1

The half-life  of carbon-14 is equal to 5730 years. The amount of substance with half-life h at any time t is equal to,
                       At = (Ao) x (1 - 0.5)^(t/h)
Substituting, 
                    At/Ao = 0.67 = 0.5^(t/5730)
The value of t from the equation is 3310.6 years.