Martin Enterprises Inventories: April 1 April 30 Raw material $20,000 $17,000 Work in process 12,000 8,000 Finished goods 30,000 39,000 Additional information for April: Raw material purchased $45,000 Direct labor payroll $36,000 Direct labor rate per hour $8.00 Overhead rate per direct labor hour $10.00 Refer to Martin Enterprises. For April, conversion cost incurred was