Question: LubeCar specializes in fast automobile oil change. The garage buys car oil in bulk at $3 per gallon. A price discount of $2.50 per gallon is available if LubeCar purchases more than 1000 gallons. The garage services approximately 150 cars per day, and each oil change requires 1.25 gallons. LubeCar stores bulk oil at the cost of $0.02 per gallon per day. Also, the cost of placing an order for bulk oil is $20. Determine the optimal inventory policy.