Question

How much of a radioactive kind of sodium will be left after 9 years if you start with 96 grams and the half-life is 3 years?

Answer 1

9 years = 12 grams

Explanation:

0 years = 96 grams

After 3 years , the amount left is 1/2 of what you started with

3 years = 1/2 *96 = 48 grams

After 3 years , the amount left is 1/2

6 years = 1/2 (48) = 24 grams

After 3 years , the amount left is 1/2

9 years = 1/2 ( 24) = 12 grams