Tesla uses a Q-system to make inventory decisions about a replacement part for a Model X. Annual demand has been forecast to be 2,500 units and the business operates 300 days per year. The standard deviation of daily demand has been forecast to be 20 units. The order lead time is 9 days. Tesla pays $8 to hold a unit for a year and $400 to place an order. Tesla’s target service level is 98%.
1. What is the optimal order quantity?
10
700
500
176.78
2. How much safety stock is required to maintain a service level of 98%?
99
107
6
123
3. Which of the following is the closest to Tesla’s annual cycle inventory cost?
4228
4984
4000
5212

On a average work day more than work place firs are reorted

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Afluid flows with a velocity field given by v=(x/t)i.. determine the local and convective accelerations when x=3 and t=1.