Math Problem Statement

Consider a single product with the following inventory data: Annual demand (D) =10 000 Ordering cost (S) = 50 Holding cost per unit per year (H) =2 Shortage cost per unit per year (P) = 5 Average daily demand (d) = 40

Using appropriate Mathematical formulas, obtain: (i) The EOQ with Shortages (ii) The Optimal Cycle Time (T) (iii) The plots for the costs (iv) The equation for the holding cost curve (v) The quantity when the holding cost and the ordering cost are the same.

Solution

To solve this problem, we will use the Economic Order Quantity (EOQ) model with shortages. Here's how we can calculate each requested item step-by-step.

(i) EOQ with Shortages

The EOQ with shortages is given by the formula:

Q=2DSHH+PQ^* = \sqrt{\frac{2DSH}{H+P}}

Where:

  • DD = Annual demand = 10,000 units
  • SS = Ordering cost = 50
  • HH = Holding cost per unit per year = 2
  • PP = Shortage cost per unit per year = 5

Let's calculate QQ^*:

Q=2×10,000×50×22+5=2,000,0007285,714.29534.52 unitsQ^* = \sqrt{\frac{2 \times 10,000 \times 50 \times 2}{2 + 5}} = \sqrt{\frac{2,000,000}{7}} \approx \sqrt{285,714.29} \approx 534.52 \text{ units}

(ii) Optimal Cycle Time (T)

The optimal cycle time TT is given by:

T=QD×365T^* = \frac{Q^*}{D} \times 365

Where QQ^* is the EOQ with shortages. Let's calculate TT^*:

T=534.5210,000×36519.52 daysT^* = \frac{534.52}{10,000} \times 365 \approx 19.52 \text{ days}

(iii) Plots for the Costs

The costs include ordering cost, holding cost, and shortage cost. We plot these costs as functions of QQ.

  • Ordering Cost: Ordering Cost=DSQ\text{Ordering Cost} = \frac{DS}{Q}
  • Holding Cost: Holding Cost=HQ22D\text{Holding Cost} = \frac{HQ^2}{2D}
  • Shortage Cost: Shortage Cost=P(DQ)Q\text{Shortage Cost} = \frac{P(D-Q)}{Q}

To generate these plots, we would plot these cost functions against QQ, the order quantity.

(iv) Equation for the Holding Cost Curve

The holding cost per cycle is given by:

Holding Cost per Cycle=HQ22D\text{Holding Cost per Cycle} = \frac{HQ^2}{2D}

This is a parabolic function where HH and DD are constants, and QQ is the variable.

(v) Quantity when Holding Cost and Ordering Cost are the Same

The holding cost and ordering cost are equal when:

HQ22D=DSQ\frac{HQ^2}{2D} = \frac{DS}{Q}

Multiplying both sides by 2Q2Q to clear the fractions:

HQ3=2DS2HQ^3 = 2DS^2

Solving for QQ:

[ Q = \sqrt[3]{\frac{2DS^2}{H}} = \sqrt[3]{\frac{2 \times 10,000 \times 50^2}{2}} \approx \sqrt[3]{25,000,000} \approx 135.72 \text{ units} ]

This is the quantity where holding cost equals ordering cost.

Summary

  1. EOQ with Shortages (Q*): Approximately 534.52 units.
  2. Optimal Cycle Time (T*): Approximately 19.52 days.
  3. Plots: These include the ordering cost, holding cost, and shortage cost functions.
  4. Holding Cost Curve: Holding Cost per Cycle=HQ22D\text{Holding Cost per Cycle} = \frac{HQ^2}{2D}.
  5. Quantity When Holding Cost Equals Ordering Cost: Approximately 135.72 units.

Would you like details on the cost plots or further explanations?

Relative Questions:

  1. How do changes in shortage costs affect the EOQ with shortages?
  2. What impact does an increase in demand have on the optimal cycle time?
  3. How does the EOQ change if the holding cost per unit increases?
  4. What is the significance of balancing holding cost and ordering cost?
  5. How do different values of SS and HH affect the total cost curve?

Tip:

When managing inventory, it's crucial to regularly update parameters like holding costs and ordering costs, as they directly influence the optimal order quantity and total costs.

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Math Problem Analysis

Mathematical Concepts

Inventory Management
Economic Order Quantity (EOQ)
Cost Analysis

Formulas

EOQ with shortages formula
Optimal Cycle Time formula
Cost functions for ordering, holding, and shortage costs

Theorems

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Suitable Grade Level

Advanced Level