Suppose a market has fourfour firms, each with 2525 percent market share. What is the Herfindahl-Hirschman Index (HHI) of concentration for this market? The HHI is nothing. (Enter your response as an integer.)

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.)

Which of the following has the largest impact on opportunity cost

The market demand curve for a popular teen magazine is given by q = 80 - 10p where p is the magazine price in dollars per issue and q is the weekly magazine circulation in units of 10,000. if the circulation is 400,000 per week at the current price, what is the consumer surplus for a teen reader with maximum willingness to pay of $3 per issue?