Final answer:
If you woke up at 11 PM after taking a nap from 2 PM to 10 PM, the possible time you would fall back asleep is 1 AM.
Step-by-step explanation:
If you took a nap at 2 PM and woke up at 10 PM, you slept for 8 hours. Then, if you fell back asleep and woke up at 11 PM, you slept for an additional 1 hour. To determine the possible time you would fall back asleep, subtract the total sleep time (9 hours) from the time you woke up (11 PM). This gives us 2 hours.
Therefore, the possible time you would fall back asleep is 2 hours after waking up at 11 PM, which would be 1 AM.