Question:
When charcoal is prepared from a living tree, it shows a disintegration rate of $15.3$ disintegration of ${ }^{14} \mathrm{C}$ per gram per minute. A sample from an ancient piece of charcoal shows ${ }^{14} \mathrm{C}$ activity to be $12.3$ disintegration per gram per minute. How old is this sample? Half-life of ${ }^{14} \mathrm{C}$ is $5730 \mathrm{y}$.
Solution:
