Question

The half-life of 14C is 5730 years. Suppose an ancient bone is found in which the ratio of 14C/12C is ¼ that found in the atmosphere and in living plants and animals. Approximately how old is the bone?

Answer 1

After 2 half-lives (1/2 * 1/2) the bone would have 1/4 the ration of Carbon 14 to Carbon 12

2 half-lives implies 2 * 5730 = 11,000 years old