Final answer:
Parwin Corporation must produce 5,000 units during the month.
Step-by-step explanation:
To determine how many units must be produced during the month, we need to calculate the net production. Net production is the difference between the units needed (planned sales) and the units on hand at the start and end of the month. In this case, the net production can be calculated as follows:
Net production = Planned sales - Units on hand at start - Units on hand at end
Net production = 30,000 - 11,500 - 12,500 = 5,000 units
Therefore, Parwin Corporation must produce 5,000 units during the month.