32 The aim of this study is to develop mathematical model for Weibull deterioration of items in inventory in declining market when the supplier offers his retailers a credit period to settle the accounts against the dues. The computational steps are explored for a retailer to determine the optimal purchase units which minimizes total inventory cost per time unit. The numerical examples are given to demonstrate the retailer’s optimal decision. A sensitivity analysis is carried out to study the variations in the optimal solution. https://jbrmr.com/details&cid=32 https://jbrmr.com/cdn/article_file/i-5_c-32.pdf Volume 04 Issue 2 5 2010-04-01 2012-02-24 no Weibull deterioration trade credit sensitivity analysis inventory none 581450 47 0 Nita H. Shah Department of Mathematics, Gujarat University, Ahmedabad Nidhi Raykundaliya Department of Mathematics, Gujarat University, Ahmedabad