Question

Carbon 14 has a half-life of 5,730 years. If a sample contained 70 mg originally, how much is left after 17,190 years.

Answer 1

Answer: Mass after three decay is 8.75 mg

Explanation: if you divide 17190 by 5730 you see three decays has happened.

So you divide mass by two three times. 70 mg :2 = 35 mg, 35 mg :2 = 17.5 mg

And 17.5 mg:2 = 8,75 mg