Problem 7: The income statement of Bulacan Corporation for the years ended December 31, 2017 and 2018 showed the following data: 2017 2018 Sales P 800,000 P 924,000 Cost of Sales 480,000 501,600 Gross Margin 320,000 422,400 Operating Expenses 180,000 220,000 Net Income P 140,000 P 202,400 Additional Data: Units Sold 80,000 88,000 Unit Selling Price P 10.00 P 10.50 Unit Costs P 6.00 P 5.70 Required: Perform a Gross Margin Analysis under the (a) Two-way; (b) Three-Way; and (c) Four-way method