From the image, it appears that we are solving an optimization problem related to inventory management for spare parts. Here's the breakdown:

Part a.

The question asks for the optimal number of spares to order, and the correct answer is given as 10 spares.

Part b.

This question asks, "Carrying no spare parts would be the best strategy for what range of shortage costs?" It asks for the answer to be rounded to two decimal places.

The answer provided seems to have been marked as complete but not entirely correct. This implies that the formula used for the shortage cost range may have been correctly applied, but there is likely an issue with the rounding or calculation.

To calculate the shortage cost (Cs) in problems like this, where demand is modeled using a Poisson distribution, you would generally apply decision theory or cost minimization principles, taking into account factors such as:

• Stockout costs ($150,000).
• Purchase price of parts ($155 each).
• Disposal costs (160% of the purchase price).

Without more specific information, I can't compute the exact shortage cost, but correcting this value typically involves applying these parameters.

Would you like me to walk you through the process of calculating the correct shortage cost range, or provide more detailed explanations? Let me know if you'd like to dive deeper into this!

Questions for deeper understanding:

1. What factors affect the optimal number of spare parts?
2. How does the Poisson distribution help in modeling demand for spares?
3. Why are disposal costs considered 160% of the purchase price in this problem?
4. How does downtime impact the total stockout cost?
5. What would be the outcome if a higher or lower number of spares was ordered?

Tip:

When dealing with Poisson distributions in inventory problems, remember that the mean demand plays a key role in determining optimal stocking policies.