Explicit formulas for the order size and reorder point in certain inventory problems

This study concentrates on distributions of leadtime demand that permit explicit solution to the lot-size, reorder point model. The optimal order size for the general case is first expressed as a function of the economic order quantity and a quantity known as the “residual mean life” in reliability theory. The concept of “no aging” is then utilized to identify a broad class of distributions for which the optimal order size can be determined explicitly, independent of the reorder point.