# Charcoal used to make prehistoric drawings on cave walls in France was analyzed. The results were 4 mg carbon-14 (parent isotope) and 60 mg nitrogen (daughter isotope). The half-life of carbon-14 is 5,730 years. How old are the cave drawings?

##### 1 Answer

The cave drawings are 22920 years old.

#### Explanation:

At the time of the drawing, there were 0 g of nitrogen 14 and 64 g of Carbon 14.

There are now 4 g.

Plugging everything in, we have:

The cave drawings are 22920 years old.