Answer and Explanation:
a. The computation of the targeted production of the finished product is shown below:
 = Expected sales units - beginning finished goods + ending finished goods 
= 160,000 - 20,000 + 5,000 
= 145,000 shells 
b. The required amount of plastic purchased is 
Plastic to be purchased = Consumed plastic + closing inventory - opening inventory
where, 
Consumed plastic is 
= 145,000 × 6 ounces 
= 870,000 ounces
Opening inventory is 60,000  ounces
And, the closing inventory is 
= 160,000  ÷ 12 months × 2 months × 6 ounces
= 160,000 
So, the purchased plastic is 
= 870,000 + 160,000 - 60000
= 970,000 ounces