Question: Twelve miles (19.2 km) of gravel road require reshaping and leveling. You estimate that a motor grader will require two passes at 3 mi/h (4.8 km/h), two passes at 4 mi/h (6.4 km/h), and one pass at 5 mi/h (8.0 km/b) to accomplish the work. How many grader hours will be required for this work if the job efficiency factor is 0.83?