Redfern Audio produces audio equipment including headphones. At the Campus Facility, it produces two wireless models, Standard and Enhanced, which differ both in the materials and components used and in the labor skill required. Data for the Campus Plant for the third quarter follow. Units produced Machine-hours Direct labor-hours Standard Enhanced Total 28,800 17,280 21,600 9,600 38,400 Direct materials costs Direct labor costs $ 576,000 345,600 11,520 21,600 $ 864,000 734,400 28,800 43,200 $ 1,440,000 Manufacturing overhead Total costs 1,080,000 760,320 $ 3,280,320 Required: Compute the predetermined overhead rate assuming that Redfern Audio uses direct material costs to allocate overhead costs. Note: Round your answer to 2 decimal places. Predetermined overhead rate % of materials cost