Kyler Manufacturing produces self$-$watering planters for use in upscale retail establishments. Sales projections for the first five months of the upcoming year show the estimated unit sales of the planters each month to be as follows: $($Click the icon to view additional information.$)20\%$ of the polypropylene required for next month's production on hand at the end of each month. The polypropylene costs $$0\mathrm{.}25$ per pound