UPSC MainsMANAGEMENT-PAPER-II201510 Marks
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Q3.

Inventory Management & Optimal Order Quantity

A Fast Food outlet stocks frozen pizzas in a refrigerated display case. The average daily demand for the pizzas is normally distributed with a mean of 8 pizzas and a standard deviation of 2.5 pizzas. The outlet operates for 300 days in a year. A vendor for packaged food distributor checks the market's inventory of frozen foods every 10 days. The lead time to receive the order is 3 days. If the purchase cost of one pizza is Rs. 300, the cost of placing an order for pizza is Rs. 200, what will be the optimal order quantity ? What will be the reorder point with a lead time of 3 days and service level of 99% ?

How to Approach

This question requires applying inventory management principles – specifically Economic Order Quantity (EOQ) and Reorder Point (ROP) calculations. The approach should involve first calculating the EOQ using the given cost parameters and demand data. Then, calculate the ROP considering lead time and desired service level, utilizing the demand distribution's standard deviation. The answer should clearly show the formulas used and the steps involved in the calculations. Finally, interpret the results in the context of the fast-food outlet's operations.

Model Answer

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Introduction

Inventory management is a critical component of operations management, particularly in industries dealing with perishable or time-sensitive goods like fast food. Maintaining optimal inventory levels is crucial to balance the costs of holding inventory against the risks of stockouts. The Economic Order Quantity (EOQ) model helps determine the ideal order quantity to minimize total inventory costs, while the Reorder Point (ROP) specifies when to place a new order to avoid shortages. This question tests the application of these concepts in a practical scenario, considering demand variability, lead time, and service level requirements.

Economic Order Quantity (EOQ) Calculation

The Economic Order Quantity (EOQ) is the order quantity that minimizes the total inventory costs, which include ordering costs and holding costs. The formula for EOQ is:

EOQ = √(2DS / H)

Where:

  • D = Annual demand
  • S = Ordering cost per order
  • H = Holding cost per unit per year

In this case:

  • D = 8 pizzas/day * 300 days/year = 2400 pizzas/year
  • S = Rs. 200/order
  • H = We need to calculate the holding cost. Assuming a cost of capital of 10% and a pizza cost of Rs. 300, the holding cost is 10% of Rs. 300 = Rs. 30/pizza/year.

Therefore:

EOQ = √(2 * 2400 * 200 / 30) = √(32000) ≈ 178.89 pizzas

Rounding to the nearest whole number, the optimal order quantity is 179 pizzas.

Reorder Point (ROP) Calculation

The Reorder Point (ROP) is the inventory level at which a new order should be placed. It considers the lead time and the demand during the lead time. The formula for ROP with safety stock is:

ROP = (Average daily demand * Lead time) + Safety Stock

Safety Stock = Z * σd * √Lead Time

Where:

  • Z = Z-score corresponding to the desired service level
  • σd = Standard deviation of daily demand

In this case:

  • Average daily demand = 8 pizzas
  • Lead time = 3 days
  • Service level = 99%
  • σd = 2.5 pizzas

For a 99% service level, the Z-score is approximately 2.33 (obtained from a standard normal distribution table).

Safety Stock = 2.33 * 2.5 * √3 ≈ 10.06 pizzas

Rounding to the nearest whole number, the safety stock is 10 pizzas.

ROP = (8 pizzas/day * 3 days) + 10 pizzas = 24 + 10 = 34 pizzas

Therefore, the reorder point with a lead time of 3 days and a service level of 99% is 34 pizzas.

Implications and Considerations

The calculated EOQ of 179 pizzas suggests that the fast-food outlet should place orders for this quantity to minimize its total inventory costs. The ROP of 34 pizzas indicates that when the inventory level drops to 34 pizzas, a new order should be placed to ensure sufficient stock during the 3-day lead time, while maintaining a 99% service level. It's important to note that these calculations are based on certain assumptions, such as constant demand and lead time. In reality, these factors may vary, and the outlet should regularly review and adjust its inventory policies accordingly.

Conclusion

In conclusion, the optimal order quantity for the fast-food outlet is 179 pizzas, and the reorder point is 34 pizzas, given the specified demand, costs, lead time, and service level. Implementing these inventory management strategies will help the outlet minimize costs, reduce the risk of stockouts, and improve overall operational efficiency. Continuous monitoring and adjustments based on actual demand patterns and lead time variations are crucial for maintaining optimal inventory control.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Economic Order Quantity (EOQ)
The EOQ is an inventory management technique used to determine the optimal order quantity that minimizes the total inventory costs, including ordering costs and holding costs.
Reorder Point (ROP)
The ROP is the inventory level at which a new order should be placed to avoid stockouts, considering the lead time and demand during that period.

Key Statistics

The food service industry in India is estimated to be worth over $65 billion in 2023 and is projected to reach $83 billion by 2028.

Source: National Restaurant Association of India (NRAI), 2023

Inventory costs typically account for 20-30% of total operating costs for businesses.

Source: APICS (Association for Supply Chain Management), 2022 (Knowledge Cutoff)

Examples

McDonald's Inventory Management

McDonald's utilizes sophisticated inventory management systems to ensure consistent product availability and minimize waste. They employ Just-In-Time (JIT) inventory principles for perishable items like lettuce and tomatoes, relying on frequent deliveries from suppliers.

Domino's Pizza Supply Chain

Domino's Pizza has invested heavily in its supply chain, including strategically located distribution centers and real-time inventory tracking, to ensure timely delivery of ingredients to its franchises.

Frequently Asked Questions

What if the demand is not normally distributed?

If the demand is not normally distributed, other inventory models and forecasting techniques may be more appropriate, such as using historical data to estimate demand probabilities or employing simulation models.

How does seasonality affect inventory management?

Seasonality requires adjusting demand forecasts and inventory levels to account for peak and off-peak periods. This may involve increasing safety stock during peak seasons and reducing it during off-peak seasons.

Topics Covered

Operations ManagementInventory ControlEOQReorder PointDemand ForecastingService Level