Western Coal, Inc., is considering an open-pit mine. The rights to mine on public land are expected to cost $25M and development of the infrastructure will cost another $12M. The mine should produce a net revenue of $8M per year for 20 years. When the mine is closed, $15M will be spent for reclamation. If the Western Coal uses an interest rate of 15%, what is the PW of this mine?

Please Provide me clear explanation with step by step procedure. Then only i will give up voting.