professor wants us to do 21% rate instead of 30% for income tax expense. how do I do that?

LO 7-3 Courtney Company uses a periodic inventory system. The following data were available: beginning inventory, 1,000 units at $35; purchases, 4,000 units at $38; operating expenses (excluding income taxes), $91,500; ending inventory per physical count at December 31, 900 units; sales price per unit, $75; and average income tax rate, 30%. Required: 1. Complete the body of the following income statements and the cost of goods sold calculation under the FIFO, LIFO, and weighted average costing methods. Inventory Costing Method Income Statement Units FIFO LIFO Weighted Average Sales Revenue $ Cost of Goods Sold* Gross Profit Operating Expenses Income from Operations Income Tax Expense Net Income *Cost of goods sold equation: Beginning Inventory $ $ $ Purchases Goods Available for Sale Ending Inventory Cost of Goods Sold 2. Between FIFO and LIFO, which method is preferable in terms of (a) maximizing income from operations or (b) minimizing income taxes? Explain. 3. What would be your answer to requirement 2 if costs were falling? Explain. You can use the template in the problem, or set it up like we did with E7-7 For income tax expense, do not use 30%; use the current 21% rate