Two pumps can be used for pumping a corrosive liquid. A pump with a brass impeller costs $800 and lasts and lasts 3 years. A pump with a stainless steel impeller costs $1,900 and lasts 5 years. A rebuild costing 300 is required after 2,000 operating hours for the brass impeller pump, while an overhaul costing $700 will be required for the stainless steel pump after 8,000 hours. If the operating cost of each pump is $1 per hour, how many hours per year must the pump be required to justify the purchase of the more expensive pump? use an interest rate of 10% per year