Gull Corp. is considering selling its old popcorn machine and replacing it with a newer one. The old machine originally cost $5,000 and has been fully depreciated. Annual costs are $4,000. A high school is willing to buy it for $2,000. New equpiment would cost $18,000 and annual operating costs would be $1,500. Both machines have an estimated useful life of 5 years.. What decision should they make?