Shaw Supply Company sells a single product and has the following average costs at a sales level of 15,000 units: Variable cost per unit ....... $2.45 Fixed cost per unit ............ 4.75 Total cost per unit ............ $7.20 Required: Determine the following amounts at a sales level of 18,000 units: a. Total variable cost b. Total fixed cost c. Variable cost per unit d. Fixed cost per unit e. Total cost per unit