Problem 3 Charlotte O’Hara founded the Tara Cosmetic Company (TCC) in 1993 when she was a student at OU. Since then, TCC has become increasingly successful: gross revenues 1994 exceeded $300,000. While preparing her 1994 tax returns, Ms. O’Hara noticed that inventories had grown substantially -the 1994 inventory to sales ratio was about 6. TCC’s tax accountant pointed out that she would require a substantial bank loan if inventory growth persistod. Wilsons’s close friend Brett was a junior at OU. Having taken POM 343, he offered to help analyze the inventory situation in return for tickets to the upcoming Pistons game against Atlanta. After a lengthy discussion, Charlotte and Brett agreed that a thorough analysis of one particular item- half-ounce bottles of “Red Earth Musk” – would provide an excellent indication of cost savings to be achieved through changes in ordering and inventory practices Brett spent a weekend rummaging through boxes full of company records, invoices and sales slips to get as much data as possible about “Red Earth Musk.” He found that demand for this cologne averaged 35 bottles per week over the last two years with a weekly mean absolute deviation of 7 bottles. TCC’s purchase price was $8 per half- ounce bottle, packaged and ready to sell. During these two years, the ordering policy has been to order 35 bottles each week. The supplier has always delivered these bottles exactly two weeks after the order was placed. Charlotte and Brett met with the accountant and figured out that the cost to TCC for placing an order was $2.50. The cost of holding a bottle in inventory for a year was difficult to assess, but all agreed that the yearly taxes, insurance and storage costs of a bottle of “Red Earth Musk” was 75 cents. They further estimated the cost of capital at 12%per year. TCC is open 5 days a week (Tuesday-Saturday), 48 weeks each year. A. What is the total annual cost of the current ordering policy of 35 B. What is the order quantity and the total annual savings if TCC were to adopt an C. If TCC were to set up a continuous review systern with a 5% chance of not fulfilling D. Develop a periodic inventory control system for TCC for their “Red Earth Musk.” bottles of “Red Earth Musk” each week? ordering policy based on an economic order quantity? demand from stock ( z-1.65), how many bottles of safety stock should they keep on hand? Use z- 2.05. State the appropriate decision rule.
Expert Answer
d = Weekly demand = 35 bottles per week
Weeks per year = 48 weeks
D = annual demand = 48 weeks x 35 units per week = 1680 bottles per year
P = Unit cost = $8 per bottle
H = annual carrying charge per unit per year = $0.75 + 12% of unit cost
H = 0.75 + 0.96 = $1.71 per bottle per year
S = ordering cost = $2.50
σ = Standard deviation of weekly demand = 7 bottles per week =
Days per week = 5 days
Part A
Current Ordering policy: Q = 35 bottles per order
Total Annual Cost:
Total annual cost = annual holding cost + annual ordering cost
Annual Holding Cost | AHC = Q/2 x H
AHC = 35/2 x $1.71 |
$29.93 | Per year |
Annual Ordering | AOC = D/Q x S
AOC = 1680/35 x $2.50 |
$120.00 | Per year |
Total annual Cost | TC = AHC + AOC
TC = 29.93 + 120.00 |
$149.93 | Per year |
Total Annual cost = $149.93
Part B:
Economic order quantity is given as follows:
Q* = √(2DS/(H)) = √(2 x 1680 x 2.50)/(1.71))
Q* = 70.087 or 70 bottles per order
Annual Holding Cost | AHC = Q*/2 x H
AHC = 70/2 x $1.71 |
$59.85 | Per year |
Annual Ordering | AOC = D/Q* x S
AOC = 1680/70 x $2.50 |
$60.00 | Per year |
Total annual Cost | TC = AHC + AOC
TC = 59.85 + 60.00 |
$119.85 | Per year |
Total Annual cost saving = $149.93 – 119.85 = $30.08 per year
Part C:
Lead time = 2 weeks
Safety Stock for Continuous review system with 5% chance of not fulfilling demand is as follows:
For CSL of 1 – 0.05 = 0.95 the z value = 1.65
SS = zσd√L
SS = (1.65)(7)(√2)
SS = 16.3342
Safety stock = 17 bottles
Part D:
According to continuous review model, the optimal order quantity is 70 bottles, thus time between order is given as follows:
T = Q*/A x no. of weeks = 70/1680 x 48 = 2 weeks
For Periodic review model with uncertain weekly demand, the order quantity or restocking level is given as follows:
R = demand during lead time and review period + Safety stock
R = Demand during protection period + safety stock
R = d(L+T) + zσd√(L+T)
Weekly
R = 35(2 + 2) + (2.05)(7)√(2 + 2)
R = 140 + 28.7
R = 168.7
According to periodic review model, the TCC should order 169 bottles next time.