Cheapest Car Rental rents cars at the Chicago airport. The car rental market consists of two segments: the short-term segment, which rents for an average of 0.5 week, and the medium-term segment, which rents for an average of 2 weeks. Cheapest currently rents an average of 200 cars a week to the short-term segment and 100 cars a week to the medium-term segment.

Approximately 20 percent of the cars returned (evenly distributed across both segments) are found to be defective and in need of repairs before they can be made available for rent again. The remaining cars not needing repairs are cleaned, filled with gas, and made available for rent. On average, there are 100 cars waiting to be cleaned. The average cost of this operation is $5 per car. Cars needing repairs spend an average of 2 weeks in the repair shop and incur an average cost of $150 per car. Assume that cars are rented as soon as they are available for rent, that is, as soon as they have been cleaned or repaired. Short-term renters pay $200 per week, while medium-term renters pay $120 per week.

1. Identify throughput, inventory, and flow time at each stage. For the cleaning activity, what is the flow rate? For the cleaning activity, what is the flow time (in weeks)? How many cars are in the repair activity?
2. What profit does Cheapest earn per week with the current system? Assume that each car loses $40 in value per week because of depreciation.
3. Cheapest is comparing two possible improvements below:

• a) Decrease time in repairs from 2 weeks to 1 week.
• b) Decrease cost per repair from $150 per car to $120 per car while keeping flow time in repairs at 2 weeks.
• Assume that the effort that is required in each case is the same. Which change do you think will be more effective? Why?