Final answer:
The vial of I-131 will contain approximately 12.5 mCi on Dec 17.
Step-by-step explanation:
To calculate the activity of the vial on Dec 17, we need to consider the half-life of I-131. The half-life of I-131 is 8.04 days.
Using the formula A = A_0 * (1/2)^(t/T), where A is the final activity, A_0 is the initial activity, t is the time in days, and T is the half-life, we can calculate the final activity.
In this case, the initial activity is 100 mCi and the time is 16 days (Dec 17 - Dec 1). Plugging in these values, we get A = 100 * (1/2)^(16/8.04) ≈ 12.5 mCi.