Question

The half-life of plutonium-238 is 87.7 years. What percentage of the atoms in a sample of plutonium-238 will remain radioactive after 263.1 years?

Answer 1

12.5

87.5

Step-by-step explanation:

Answer 2

263.1 is exactly three half-life, so the remaining portion is (1/2 x 1/2 x 1/2) of the original sample. That's 1/8 which is 12.5% .