Roberts Corporation has two manufacturing departments: Forming and Assembly. The following data were available at the beginning of the year: Forming 7,000 Assembly 3,000 Estimated total labor hours $40,600 $12,900 Estimated total fixed manufacturing overhead Estimated variable manufacturing overhead per labor hour $1.30 $2.80 If the company uses a single plantwide predetermined overhead rate based on labor hours, then what is the predetermined overhead rate at Roberts? $4.10 per labor hour $4.87 per labor hour O $6.62 per labor hour O $7.10 per labor hour None of the above