If there were 7,000 pounds of raw materials on hand on march 1, 14,000 pounds are desired for inventory at march 31, and 42,000 pounds are required for manufacturing in march, how many pounds of raw m

If there were 7,000 pounds of raw materials on hand on march 1, 14,000 pounds are desired for inventory at march 31, and 42,000 pounds are required for manufacturing in march, how many pounds of raw materials should be purchased in march?