Math Problem Statement

A company begins a review of ordering policies for its continuous review system by checking the policies for a sample of SKUs. The following data are given to you. Demand (D) = 64 units per week (assume 52 weeks per year) Ordering cost (S) = $ 50 per order Holding cost = $13 unit/year Lead time (L) = 2 weeks Standard Deviation of weekly demand = 12 units Cycle-service level = 88% a. What is the EOQ for this item? 160 b. What is the desired SS (safety stock)? c. What is the reorder point?

Solution

Let's break down the calculations for each part:

Given Data:

  • Annual Demand D=64D = 64 units/week × 52 weeks = 33283328 units/year
  • Ordering Cost S=50S = 50 dollars per order
  • Holding Cost H=13H = 13 dollars per unit per year
  • Lead Time L=2L = 2 weeks
  • Standard Deviation of Weekly Demand σd=12\sigma_d = 12 units
  • Cycle-Service Level CSL=88%\text{CSL} = 88\%

The Economic Order Quantity (EOQ) has been calculated as 160 units.

b. Calculating Safety Stock (SS)

To calculate Safety Stock (SS), we use the following formula:

SS=z×σLSS = z \times \sigma_L

where:

  • zz is the z-score for the desired cycle-service level,
  • σL\sigma_L is the standard deviation of demand during lead time, calculated as:

σL=σd×L\sigma_L = \sigma_d \times \sqrt{L}

  1. Find σL\sigma_L: σL=12×2=12×1.414=16.9717\sigma_L = 12 \times \sqrt{2} = 12 \times 1.414 = 16.97 \approx 17

  2. Determine zz for an 88% cycle-service level: For a cycle-service level of 88%, we find the corresponding z-score from the z-table, which is approximately 1.175.

  3. Calculate SSSS: SS=1.175×1720SS = 1.175 \times 17 \approx 20

Therefore, the desired safety stock (SS) is 20 units.

c. Calculating the Reorder Point (ROP)

The reorder point (ROP) considers both the average demand during lead time and the safety stock:

ROP=(d×L)+SSROP = (d \times L) + SS

where:

  • dd is the weekly demand, and
  • LL is the lead time in weeks.
  1. Calculate d×Ld \times L: d×L=64×2=128d \times L = 64 \times 2 = 128

  2. Calculate ROPROP: ROP=128+20=148ROP = 128 + 20 = 148

Therefore, the reorder point (ROP) is 148 units.


Summary of Answers:

  • b. Safety Stock (SS): 20 units
  • c. Reorder Point (ROP): 148 units

Would you like further details on any part of the calculations?

Related Questions

  1. How would an increase in lead time impact the safety stock?
  2. If the cycle-service level were raised to 95%, what would the new safety stock be?
  3. How does demand variability affect the reorder point?
  4. What is the impact on EOQ if the holding cost per unit changes?
  5. How can the cycle-service level be balanced with cost considerations?

Tip:

For a continuous review system, frequently check both demand patterns and lead time variability, as changes in these factors can directly impact reorder points and safety stock.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Inventory Management
Continuous Review System
Probability and Statistics

Formulas

EOQ = sqrt((2 * D * S) / H)
Safety Stock (SS) = z * σ_L, where σ_L = σ_d * sqrt(L)
Reorder Point (ROP) = (d * L) + SS

Theorems

Economic Order Quantity (EOQ) Model
Standard Normal Distribution

Suitable Grade Level

Undergraduate (Business or Operations Management)