Need help with a math carbon 14; decay and half life problem help me please ?

Carbon 14 is used to date organic remains in archeology. It has a half life of about 5730 years. In about 5730 years, one half of the amount of c14 originally present in a bone or piece of charcoal will be lost to radioactive decay. How long will it take for the c14 in a bone to decrease to 1/16 of its original amount? Explain how you got the answer. Is this related to geometric sequences? why or why not?