The halflife of Carbon14 is about 5700 years You have found

The half-life of Carbon-14 is about 5700 years. You have found a fossil in sedimentary rocks that have 1/128 the normal (modern) expected ratio of Carbon-14C. Based on this information, you estimate that it is about _______ years old.

44

5700

39,900

729,600

Solution

The fossil in 39,900 years old. At 1/128 the carbon-14 of living organisms, it has gone through seven half-lives of carbon-14 (5700 years x 7 = 39,900 years)