DeWitt Industries has adopted the following production budget for the first 4 months of 2017. Each unit requires 3 pounds of raw materials costing $3 per pound. On December 31, 2016, the ending raw materials inventory was 9, 330 pounds. Management wants to have a raw materials inventory at the end of the month equal to 20% of next month's production requirements. Prepare a direct materials purchases budget by month for the first quarter