An EPQ model under process unreliability without calculus

Huang et al. [Journal of Information & Optimization Sciences, Vol. 29, No. 5, pp 923–929] investigated an optimal inventory policy for imperfect quality production system where the products produced are a mixture of perfect and imperfect quality. But we fi nd a small shortcoming in their model. Therefore, this article willcorrect the shortcoming and use two methods to fi nd the optimal solution under the annual profi t maximized without derivatives. The proposed methods are easy-to-understand and simple-to-use.