 Let us look at an example of time flexibility strategy. Let us suppose we have again 6 months demand or January again there it is 1700 units of demand at February 3000, March 3200, April then it goes down to 2400 and June again goes down to 2200. So this is our demand and we have to meet this demand using time flexibility. In this our assumption is that 8 hours shift or per day or there are 25 days per month. That means all 6 months we assume that there are 25 days per month. Beginning forces can be included and that is 30 workers or beginning inventory is 100 units of inventory and on the basis of this we have to use time flexibility to solve this problem that how many units we have to produce over time and how many units we have to utilize under time. There is another assumption which is important and it is usually in the policy of companies that a worker does not over time than a particular number of hours. The reason being that when a worker over time does not over time, then due to that productivity falls, defective products start to produce, quality effect occurs, then the management curtail it and says that it will not produce more than this quantity. In this case more than 30% of regular time a worker cannot work in overtime. To meet the demand, basically that is the policy of our overtime in this case. If we utilize this overtime we cannot meet the demand because our constraint is more than 30% we cannot utilize. In that case we can then use subcontracting to meet the demand in a given month. The cost data that we have provided on the basis of this we have material cost which is in this case $10 per unit. Inventory holding cost is $2 per unit per month. Stock out cost we have provided is $5 per unit per month. If a unit is stock out in a month then its cost will be $5. Hiring cost we have provided is $300 per worker. Lay off cost if we fire a worker then it is $500 per worker. Labor hours required per unit is 4 hours. So that means that a worker can produce 2 units in a day because there are 8 hours per worker per day so if a unit is being produced in 4 hours then basically we can say that a worker can produce 2 units in a day. Regular time cost is $4 per hour whereas overtime cost is one and a half time of regular time cost which is in this case $6 per hour and cost of subcontracting is basically $30 per unit. If we subcontract then we have to pay $30 per unit.