Answer:
The turkey has to be put in the oven at 7:10 AM.
Explanation:
We have:
Turkey stuffed with 16 pounds
Since the time of cooking is 15 minutes per pound with an addition of 5 minutes per pound when the turkey is stuffed, hence we have:

Therefore, the total time of cooking is 320 minutes or 5 hours plus 20 minutes.
If they plan to eat at 1:00 PM with 30 minutes for cooling and carving, then:

Hence, the turkey has to be put in the oven at 7:10 AM.
I hope it helps you!