Slower Company uses a job-order cost system in each of its two manufacturing departments. Manufacturing overhead is applied to jobs on the basis of direct labour cost in Department A and machine hours in Department B. In establishing the predetermined overhead rates for 2020, the following estimates were made for the year: Department A B Manufacturing overhead. $1,056,000 $840,000 Direct labour cost................ 264,000 600,000 Direct labour hours.. 12,000 40,000 Machine hours.... 75,000 84,000 During January, the job cost sheet showed the following costs and production data: Jobs 14 15 Direct materials used. Direct labour cost...... Manufacturing overhead incurred.. Direct labour hours...... Machine hours..... $34,000 $31,000 24,000 25,500 65,000 35,000 2,000 1,700 5,000 4,000 Instructions a) Calculate the predetermined overhead rate for each department. (4 points) b) Calculate the total manufacturing cost assigned to jobs 14 and 15 in January. (4 points) c) What is the purpose of job cost accounting? (2 points)