Sheridan sells a learning system that helps preschool and elementary students learn basic math facts and concepts. The company income statement from last month is as follows: Total Per unit Sales Revenue is $700,000 $50 Variable expenses $315,000 $22.50 Contribution margin $385,000 $27.50 Fixed expenses $250,250 Operating Income is $134,750 a. What is Sheridans contribution margin ratio? Its variable cost ratio?