Diamond Corporation uses a job-order costing system with a plant wide predetermined overhead rate that is based on machine-hours. At the beginning of the year, the company made the following estimates: Machine hours...... ..250,000 Estimated total manufacturing overhead costs.... $1,250,000 Required: 1. Compute the plantwide predetermined overhead rate. 2. During the year, Job 345B was started and completed. Given the following information, compute the total manufacturing cost and the per unit cost of Job 345B: Direct Material............... $880 Direct Labor......... $285 Machine-hours incurred......45 Units produced...... 200