An economic order quantity model for items with two levels of storage for a linear trend in demand

A deterministic inventory model with two levels of storage (own warehouse and rented warehouse) is studied by considering a linear (positive) trend in demand. Firstly, the model is formulated and solved without allowing backlogging. Secondly, the model is reformulated and solved under the assumptions that shortages in inventory are allowed and backlogged. The results are illustrated with the help of numerical examples.