Answer:
The turkey should go to the oven at 10:15
Step-by-step explanation:
1. As you want to eat at 4 o´clock you should calculate how many time you will spend cooking and carving the turkey, so:
Time cooking the turkey = 5.5 hours
Time carving the turkey = 
Total time preparing the turkey = 5.5hours + 0.25hours
Total time preparing the turkey = 5.75 hours
2. Subtract the total time that you will spend preparing the turkey from the 16 hours:
16 - 5.75 = 10.25hours

Therefore, the turkey should go to the oven at 10:15