Susan Wilson is opening a small flower shop that will focus primarily on delivery, though it will provide a small showroom for walk-in customers. A local florist is retiring and selling her small flower shop to Susan for $137475. The shop has a remaining life of 20 years. Susan expects to have incremental revenues of $76375 per year and pay approximately 60% of revenues in operating costs. What is the payback period for Susans flower shop?