In: Operations Management
Ram Roy’s firm has developed the following supply, demand, cost, and inventory data. Allocate production capacity to meet demand at a minimum cost using the transportation method. What is the cost? Assume that the initial inventory has no holding cost in the first period and backorders are not permitted.
Initial Inventory 20 Units
Regular Time cost per unit $100
Overtime cost per unit $160
Sub contract cost per unit $250
Carrying cost per unit per month $6
Supply Table
Period | Regular Time | Overtime | Subcontract |
Demand Forecast |
1 | 30 | 15 | 5 | 40 |
2 | 30 | 15 | 5 | 45 |
3 | 40 | 15 | 5 | 55 |
Our goal here is to minimize the costs of supply for the overall demand.
Total Demand Forecast for three periods = 140
Inventory in Hand = 20
Period 1:
Production for Period 1 = 30 Regular + 20 Inventory = 50 units
Demand for Period 1 = 40 units
Inventory after period 1 = 10 units
Cost for Period 1 = 30*$100 = $3000
Inventory Carrying Cost from Period 1 to Period 2 = 10*$6 = $60
Period 2:
Production for Period 2 = 30 Regular + 10 Inventory + 5 Overtime = 45 units
Demand for Period 2 = 45 units
Inventory after period 2 = 0 units
Cost for Period 3 = 30*$100 + 5*$160 = $3800
Inventory Carrying Cost from Period 2 to Period 3 = $0
Period 3:
Production for Period 3 = 40 Regular + 15 Overtime = 55 units
Demand for Period 3 = 55 units
Inventory after period 3 = 0 units
Cost for Period 3 = 40*$100 + 15*$160 = $6400
Inventory Carrying Cost from Period 2 to Period 3 = $0
Total Cost
Total Cost = Period 1 + period 2 Period 3
= $3000+ $60 + $3800 + $6400
= $13260