3. The expected costs for the Maintenance Department of Staler, Inc., for the coming year include: Fixed costs (salaries, tools): $64,900 per year Variable costs (supplies): $1.35 per maintenance hour Estimated usage by: Assembly Department Fabricating Department Packaging Department Total maintenance hours 4,500 6,700 10.800 22.000 Actual usage by: Assembly Department Fabricating Department Packaging Department Total maintenance hours 3,960 6,800 10,000 20,760 i. Calculate a single charging rate for the Maintenance Department. i. Use this rate to assign the costs of the Maintenance Department to the user departments based on actual usage. Calculate the total amount charged for maintenance for the year