A living plant contains about the same fraction of carbon-14 as atmospheric carbon dioxide. The observed rate

Question:

A living plant contains about the same fraction of carbon-14 as atmospheric carbon dioxide. The observed rate of decay of carbon-14 from a living plant is 15.3 counts per minute per gram of carbon. How many counts per minute per gram of carbon will be measured from a 15,000-year- old sample? Will radiocarbon dating w’ork well for small samples of 10 mg or less?