my teacher gave us this question and im lost.

Anthropologists have found an old campsite in a remote location. After calculating the carbon-14 in the wood, they determine that there is 1/8 of the original material left. How many half-lives of carbon-14 have decayed and how many years old is the campsite?

The campsite is three half-lives old.

(1/2)^3 = 1/8

One C-14 half life is about 5570 years.

3 x 5570 = ____ yrs