A proposed nuclear power plant will cost $1.7 billion to build and then will produce cash flows of $250 million a year for 15 years. After that period (in year 15), it must be decommissioned at a cost of $850 million. Note: Negative amounts should be indicated by a minus sign. Do not round intermediate calculations. Enter your answers in billions rounded to 3 decimal places. a. What is the NPV of the project if the discount rate is 5% ? b. What is the NPV of the project if the discount rate is 18%