Cory is considering buying a new, fully insulated and enclosed deer stand at a cost of $1,000. He wont have a salvage value in the future but will cost him $100 to dispose of when he is done using it. He considers the advantages of owning and hunting from the deer stand will be $250 per year. Cory's interest rate is 15%. How many years must Cory hunt from the deer stand in order for the purchase to be economically attractive?