Identify the cost formula the company should use if it wants to maximize gross profit and net income?

Novak-Mart Centre Inc. opened for business on May 1, and uses a perpetual inventory system. During May, the company had the following purchases and sales for one of its products: Purchases Units Unit Cost $100 Sales Unit Price Date May 1 3 Units 120 80 $237 8 100 109 80 262 60 115 13 15 20 27 60 40 287 310