Answer Happy

Please help with number 2. Others are correct.
ANSWER IS NOT 8.3, 0.07798, 20 or 2.4e5
Homework: Theory Of Radiotracers And Generators Deadline: 100% until Wednesday, July 6 at 11:59 PM Radionuclides used in PET ✓2✓ ✓ 1) 82Rb with T1/2 = 1.25min, like $¹Rb, is a positron emitter that is useful for heart perfusion imaging. It can be produced by the natural decay of 82 Sr (T1/2 = 25 days). What kind of equilibrium do they undergo? No equilibrium Transient equlibrium Secular equlibrium Submit 2) Suppose you have a sample with 100 mCi of 82 Sr. When will the activity of 82Rb reach over 99% of the activity of 82 Sr? 3) How much daughter activity (Question 1) will there be after 20 minutes? 100 min Submit Help 57.4 mCi Submit 4) How much daughter activity (Question 1) will there be after 20 days? mCi Submit