Please don't solve with Lingo

1) Demand for a product for the next 4 months is given as 650, 400, 700, 500 respectively in aggregate units. Every worker can produce 2.5 aggregate units during any month. Production cost is 5 liras per unit. Overtime production or subcontracting is not possible. Inventory holding cost is 9 liras per unit per month. Undertime cost is 4 liras per unit (calculated for each aggregate unit of unused capacity). Backordering is not allowed. Beginning inventory is zero, ending inventory should be planned to be zero. a) (15pts) What should be the minimum number of workers at the beginning of the first month so that demand towards the end of the planning horizon is fulfilled, given that backorders are not allowed. (Assume that the initial workforce size will remain constant.) b) (15pts) Based on the constant workforce strategy in part-(a) determine a feasible aggregate plan given that there are 270 workers and backordering is not allowed. For this solution write down the values of all decision variables (monthly production quantities P1, P2, P3, P4; inventory-on-hand at the end of months 11, 12, 13, 14 ; undertime units U, U2, U3, U4) as well as the cost of this plan