For this problem, we use the decay equation which is expressed as:
An = (Ao)e^-kt
where An is the amount left in t time, Ao is the initial amount and k is a constant.
We first calculate the value of k as follows:
An = (Ao)e^-kt
0.5 = e^-k(8)
k = 0.087
We calculate the time as follows:
An = (Ao)e^-kt
15.625 = 250e^-0.087t
t = 31.87 days
