Spring Street 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:

Engine parts .....................................................$ 875,000

Shop direct labor ...............................................660,000

Shop and repair equipment depreciation................... 44,500

Shop supervisor salaries.......................................... 138,000

Shop property taxes............................................... 27,500

Shop supplies ...............................................10,000

Advertising expense............................................... 22,100

Administrative office salaries.................................... 73,500

Administrative office depreciation expense.................. 8,600

Total costs and expenses .................................$1,859,200

The average shop direct labor rate is $30 per hour.

Determine the predetermined shop overhead rate per direct labor hour.