Jason processing co. uses the average costing method and reported a beginning inventory of 5,000 units that were 20% complete with respect to materials in one department. during the month, 11,000 units were started; 8,000 units were finished; ending inventory amounted to 8,000 units that were 60% complete with respect to materials. total materials cost during the period for work in process should be spread over to how many units: