Selected financial data for Spark Enterprises follows for a production level of 120,000 units: Total fixed costs Total costs (fixed and variable) $300,000 $450,000 a. Calculate the variable cost per unit. b. If Flash Corporation makes 75,000 units, calculate the fixed cost per unit. C. If Flash Corporation makes 160,000 units, calculate the total variable costs. d. If Flash Corporation makes 180,000 units, calculate the total costs