Can't figure this one out.

n G... Mail - Cleveland G.... Connect - To Do As... JWU | Private Dog Up! Franks is looking at a new sausage system with an installed cost of $795,600 This cost will be depreciated straight-line to zero over the project's 7-year life, at the end of which the sausage system can be scrapped for $122,400. The sausage system will save the firm $244,800 per year in pretax operating costs, and the system requires an initial investment in net working capital of $57.120. If the tax rate is 25 percent and the discount rate is 15 percent, what is the NPV of this project