Final answer:
The half-life of Actinium-227 is approximately 18.4 years.
Step-by-step explanation:
The half-life of Actinium-227 can be found using the decay function provided.
The decay function is given by the equation y' = -0.0321y.
The half-life is the time it takes for half of the initial amount to decay, so when y' = -0.0321y, we can set y' = -0.5yo (where yo is the initial amount) and solve for t.
-0.5yo = -0.0321yo
0.468 = e^(-0.0321t)
t = ln(0.468) / (-0.0321)
= 18.4 years
Therefore, the half-life of Actinium-227 is approximately 18.4 years.