Express Mailbox produces decorative mailboxes. The company's average cost per unit is $28.43 when it produces 1,800 mailboxes. Read the requirements. Requirement 1. What is the total cost of producing 1,800 mailboxes? The total cost of producing 1,800 mailboxes is Requirements 1. What is the total cost of producing 1,800 mailboxes? 2. If $24,174 of the total costs are fixed, what is the variable cost of producing each mailbox? 3. Write Express Mailbox's cost equation. 4. If the plant manager uses the average cost per unit to predict total costs, what would the forecast be for 1,900 mailboxes? 5. If the plant manager uses the cost equation to predict total costs, what would the forecast be for 1,900 mailboxes? 6. What is the dollar difference between your answers to questions 4 and 5 ? Which approach to forecasting costs is appropriate? Why