Final answer:
The correct equation representing the number of care packages volunteers still need to fill is P = 522 - 190, which can be used to find the number of packages filled so far.
Step-by-step explanation:
The question asks for an equation that represents the number of care packages (P) the volunteers still need to fill. They aim to fill a total of 522 packages and have 190 packages left to fill. To find the number of packages filled so far, we can subtract the number of packages left to fill from the total number of packages they aim to fill. So, the correct equation would be P = 522 - 190.