Exotic Engine Shop uses a job order cost system to determine the cost of performing engine repair work. Estimated costs and expenses for the coming period are as follows: The average shop direct labor rate is $40.00 per hour. Determine the predetermined shop overhead rate per direct labor hour. Hints: 1. Not all of the costs and expenses represent factory overhead; 2 . Determine the estimated activify base by dividing the shop direct labor cost by the direct labor rate