1. Dangote's Oil Refinery's revenues and cost data for 2020 are as follows: Revenues $600,000 Cost of goods sold (all variable costs) 300,000 Gross margin 300,000 Operating costs: Salaries fixed $140,000 Sales commissions (12% of sales) 72,000 Depreciation of equipment and fixtures 10,000 Store rent ($3,500 per month) 42,000 Other operating costs 45,000 309,000 Operating income (loss) $ 19,000) Mr. Dangote, the owner of the company, is unhappy with the operating results. An analysis of other operating costs reveals that it includes $30,000 variable costs, which vary with sales volume, and $15,000 (fixed) costs. Required: 1. Compute the contribution margin of Dangote's oil refinery. 2. Compute the contribution margin percentage