Note: The quantity of material to be purchased for March requires determining the units to be produced for April and then the material needed for production for April. 1,900 + .05(1,800) - .05(1,900) = 1,895 April units to be produced. (1,895)(2 lbs) = 3,790. Then material to be purchased for March is 4,180 + .05(3,790) - .05(4,180) = 4,160.5.