A simple method to locate the optimal solution of the inventory model with variable lead time

This article tries to find the optimal order quantity and optimal lead time of a mixture inventory model. First, this article establishes a principle to compare the optimal order quantities at all the lengths of lead times with components crashed to their minimum duration. Second, some lemmas are developed to reveal the effects of parameters and to simplify the solution procedure of Ouyang, Yeh and Wu. Finally, some numerical examples are given to illustrate all lemmas in this article.