A sample of radon has an activity of 80,000 Bq. If the half-life of radon is 15 h, how long before the sample's activity is 5,000 Bq?

Answer 1

Half life = 15h
Activity
A(t)=A(0)*2^(-t/15)
Solve for t in
A(t)=5000=80000(2^(-t/15))
to get t=60 (hours)