The cost formulas for Swan Company's manufacturing overhead costs are given below. The costs cover a range of 20,000 to 40,000 machine-hours. Required: Prepare a flexible manufacturing overhead budget assuming a budgeted level of activity of 30,000 machine-hours. Include all costs in your flexible budget. Calculate the predetermined overhead rate. Predetermined Overhead Rate = Calculate the variable portion of the predetermined overhead rate. /ariable Portion of the Predetermined Overhead Rate = Calculate the fixed portion of the predetermined overhead rate. iixed Portion of the Predetermined Overhead Rate =