Answer:
The purchases of material Z should be of 656000 pounds.
Step-by-step explanation:
The purchases of material Z should be such that they meet the desired closing inventory requirement of product Z along with producing enough units to meet the production requirements for the period which are left after the opening inventory has been used. Or we can also say that the purchases should be enough to meet the closing inventory and the Production requirements less the opening inventory.
Thus, purchases = Closing Inventory + Total Production Requirements - Opening inventory
The amount of material Z needed to produce 212000 units = 212000 * 3 = 636000 pounds
Purchases = 410000 + 636000 - 390000
Purchases = 656000 pounds