Johnston, Inc. manufactures bookcases and uses an activity-based costing system. Johnston's activity areas and related data follow: (Click the icon to view the activity areas and related data.) (Click the icon to view the totals for quantities, direct materials costs, and other data.) Read the Requirement 1. Compute the manufacturing product cost per unit of each type of bookcase. (Enter a "0" for any zero-balances.) Data table Data table