Question

If a sample originally had 120 atoms of carbon-14, how many atoms will remain after 17,145 years? Assume the half life of C14 is 5715 years.

Answer 1

15 atoms left after 3 half lives

Step-by-step explanation:

17145 y / 5715 y/halflife = 3 half lives

(1/2)^3 = 1/8 of original is left

1/8 ( 120 atoms) = 15 atoms left