University students, studying the activity of a particular radioactive isotope which had a half-life of 12.0 hours. If the original activity of the sample was 448 kBq, what would the activity be 3.00 days later?

Answer 1

Three days is six 12-hour intervals, which is six half-lives.

Multiply the original activity by (1/2)^6 = 1/64

448/64 =__ kBq