Final answer:
An 18 pound turkey should be cooked for 4.5 hours, following the guideline of 1 hour for every 4 pounds. Therefore, if cooked for only 4 hours, it was not cooked long enough by 0.5 hours.
Step-by-step explanation:
To determine if an 18 pound turkey was cooked long enough when baked for 4 hours, we use the given guideline that it should be cooked for about 1 hour for every four pounds of meat. Firstly, we calculate the total required cooking time for the turkey:
- Divide the turkey's weight by the rate of cooking time per pound, which is 18 pounds ÷ 4 pounds/hour = 4.5 hours.
The calculation shows that the turkey should have been cooked for 4.5 hours instead of 4 hours. Hence, the turkey was not cooked long enough. To ensure it is properly cooked, it should be kept in the oven for an additional 0.5 hours or 30 minutes:
- Total cooking time = 4 hours (already cooked) + 0.5 hours (additional needed) = 4.5 hours.