An engineering consulting office is considering whether to purchase or lease a computer printing system. The small system can be purchased for $40, 000 with a life of four years and salvage value of $2, 000. Operating expenses are expected to be $60 per day and annual maintenance to be $500 per year. An identical system can be leased for $125 per day, including maintenance and operating expenses. Determine the number of days per year that the system would have to be used to make the purchase economical. The desired ROI of the firm is 15%