Cantracom Inc. plans to purchase new oil-field equipment. The company's investment analyst has made the following estimates: New equipment cost, including installation and training $140,000 Salvage value of new equipment at the end of its useful life $20,000 New equipment's useful life 4 years Annual increase in sales $82,000 Annual increase in costs other than depreciation $19,000 Income tax rate 30% Discount rate (RRR) 7% Help finding Net Present Value?