@X@user.full_name@X@ @GMU: Radioactive substances decay by f…
@X@user.full_name@X@ @GMU: Radioactive substances decay by first-order kinetics. How many years would be required for a sample containing plutonium-94 to decrease to 55.44% of its initial activity? The half-life of plutonium-94 is 2.44e4 years.