The Central Valley Company is a merchandising firm that sells a single product. The company's revenues and expenses for the last three months are presented below: CENTRAL VALLEY COMPANY Comparative Income Statement for the Second Quarter April 4,500 $630,000 252,000 May 5,250 $735,000 294,000 June 6,000 $840,000 336,000 378,000 441,000 504,000 Sales in units Sales revenue Less: cost of goods sold Gross margin Less: operating expenses Shipping expense Advertising expense Salaries and commissions Insurance expense Depreciation expense Total operating expenses Net income 56,000 70,000 143,000 63,500 70,000 161,750 71,000 70,000 180,500 9,000 42.000 9,000 42,000 9,000 42.000 320,000 346,250 372.500 $58,000 $94,750 $131,500 Required: a. Determine which expenses are mixed and, by use of the high-low method, separate each mixed expense into its variable and fixed components. State the cost formula for each mixed expense. b. Compute the company's total contribution margin for May