The National Tire Company manufactures only one type of tire and wants to plan its production and inventory levels for the next five months. Company policy is to schedule all of its overtime production during one month. The table below provides the relevant data for each month, where the inventory level requirements refer to the level at the end of each month. Other relevant information is as follows:

- NTC estimates that it costs $1 to hold one tire in inventory from one month to the next.

- NTC currently has an inventory level of 4,000 tires. NTC wants to meet its demand with no backorders. All demand must be met.

Construct a spreadsheet model to solve for the production and inventory plan. You may want to draw a network diagram first.

Month 1 Demand 12000 18000 24000 20000 22000 Max production level 18000 18000 30000 18000 18000 Production cost 11 11 11.5 11 11 Min production level 6000 6000 6000 6000 6000 Max inventory level 10000 10000 15000 10000 10000 2 3 Min inventory level 2000 2000 2000 2000 2000 4 5