Please solve without excel

06.01-PR006 Carlisle Company has been cited and must invest in equipment to reduce stack emissions or face EPA fines of $18,500 per year. An emission reduction filter will cost $75,000 and have an expected life of 5 years. Carlisle's MARR is 10%/yr. a. What is the internal rate of return of this investment? b. What is the decision rule for judging the attractiveness of investments based on internal rate of return? c. Is the filter economically justified