You own a coal mine and are considering selling it to a company to open it. However, this company only knows how to mine but not how to make sure the site be cleaned and maintained at environmental standards. So, it will be your responsibility if you decide to sell. The company offer you an immediate payment of $20 million to buy the mine. The cleaning and maintenance are expected to cost $2 million per year in perpetuity. What does the IRR rule say about whether you should accept this opportunity? If the interest rate is 8%, what does the NPV rule say? Which rule will you follow if they deviate?