A flood control project has construction costs during the first year of $15 million, during the second year of $6 million, and during the third year of $1 million. It is completed at the end of the third year and thereafter incurs an annual operating cost of $0.2 million per year (the operating cost starts at the end of year 4). Benefits from the project begin during year 5 and are valued at $1.5 million in that year, growing at a 0.02 compound rate of increase out to the planning horizon (analysis period) of 50 years. The interest rate is 0.06. What is the present worth of cost

You are thinking of making your mansion more energy efficient by replacing some of the light bulbs with compact fluorescent bulbs, and insulating part or all of your exterior walls. each compact fluorescent light bulb costs $4 and saves you an average of $2 per year in energy costs, and each square foot of wall insulation costs $1 and saves you an average of $0.20 per year in energy costs.† your mansion has 150 light fittings and 3000 sq ft of uninsulated exterior wall. to impress your friends, you would like to spend as much as possible, but save no more than $750 per year in energy costs (you are proud of your large utility bills). how many compact fluorescent light bulbs and how many square feet of insulation should you purchase? how much will you save in energy costs per year? (if an answer does not exist, enter dne.)