Final answer:
The individual can receive an additional 400cc of fluid from 6 pm to midnight, after having already received 800cc between midnight and 6 pm, considering the total limit of 1200cc in a 24-hour period.
Step-by-step explanation:
If an individual can receive a total of up to 1200cc in a 24-hour period and they already received 800cc of fluid between midnight and 6 pm, the remaining amount they can have in the 6 hours between 6 pm and the next midnight is calculated by subtracting the amount already received from the total allowed. Here's the calculation:
Total allowed: 1200cc
Already received: 800cc
Remaining amount: 1200cc - 800cc = 400cc
Therefore, the individual can receive an additional 400cc of fluid from 6 pm to midnight.