Paul Restaurant is considering the purchase of a $10,700 souffl maker. The souffl maker has an economic life of 7 years and will be fully depreciated by the straight-line method. The machine will produce 1,600 souffls per year, with each costing $2.40 to make and priced at $4.85. The discount rate is 13 percent and the tax rate is 21 percent. What is the NPV of the project?

Please explain what PVIFA is and solve in excel. thanks