- Develop the mathema1ical model in the Word document. . Solve the problem in Excel - Develop a plan in the Word document and explain when and how many.r products should be ordered in order to minimise the total cost. . Recalculate the optimal value of objective function {total cost with the new assumption that the holding cost is applied to the average inventory [not ending inventory). Queson 3 Use 'Lot for Lot' heuristic method and compute the total cost where the planning period is not nite and keeps rolling. So, the easiest Heuris1ic is if we are looking at 12 months, the simplest thing to do is make an order ever},r month. That is called lot for lot Heuristic