If the turkey is stuffed so time it will be cook is:
T = 22 lb ( 20 min/ lb) = 440 min = 7 hrs and 20 min
If the turkey is unstuffed so the timme it will be cook is:
T = 22 lb (15 min / lb) = 330 min = 5 hrs and 30 min
If she wants dinner at 4:00 pm and it should 30 min berfore it is served
If the turket is stuffed so ii should be placed in the oven at 8:10 am
If the turkey is un stuffed it should be placed at the oven at 10:00 am