Carco uses robots to manufacture cars. The following demands for cars must be met (not necessarily on time, but all demands must be met by end of quarter 4):

At the beginning of the first quarter, Carco has two robots. Robots can be purchased at the beginning of each quarter, but a maximum of two per quarter can be purchased. Each robot can build up to 200 cars per quarter. It costs $5000 to purchase a robot. Each quarter, a robot incurs $500 in maintenance costs (even if it is not being used to build any cars). Robots can also be sold at the beginning of each quarter for $3000. At the end of each quarter, a holding cost of $200 for each car in inventory is incurred. If any demand is backlogged, a cost of $300 per car is incurred for each quarter the customer must wait. At the end of quarter 4, Carco must have at least two robots.

a. Develop a model in excel to minimize the total cost incurred in meeting the next four quarters' demands for cars.