How to calculate desired ending direct material?

Each unit requires 5 pounds of raw materials costing $4 per pound. On December 31, 2016, the ending raw materials inventory was 9,260 pounds. Management wants to have a raw materials inventory at the end of the month equal to 20% of next months production requirements.

DeWitt Industries has adopted the following production budget for the first 4 months of 2017. Month Units Month Units 5,200 4,230 10,100 March January February 8,400 April Each unit requires 5 pounds of raw materials costing $4 per pound. On December 31, 2016, the ending raw materials inventory was 9,260 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