Rocky Mountain Lumber Company is considering purchasing a new wood saw that costs $50,000. The saw will generate revenues of $100,000 per year for four years. The cost of materials and labor needed to generate these revenues will total $60,000 per year, and other cash expenses will be $10,000 per year. Depreciation expense will be $12,500 per year over the four years. The machine is expected to sell for $950 after-taxes at the end of its four-year life. Rocky Mountain’s tax rate is 34 percent, and its opportunity cost of capital is 10 percent. What is the NPV of this investment?