Suppose a competitive firm and a monopolist are both charging $5 for their respective outputs. one can infer that:
a. marginal revenue is $5 for both firms.
b. marginal revenue is $5 for the competitive firm and less than $5 for the monopolist.
c. marginal revenue is less than $5 for both firms.
d. the competitive firm is charging too much and the monopolist too little.

The market for corn in country a is highly competitive. at the current market price of $5/bushel there is a shortage of 100,000 bushels of corn in this country. media reports claim that the price of corn will rise drastically in the near future. according to these reports, the neighboring country b had witnessed a similar situation recently. at the same price, the shortage in country b was also 100,000 bushels and eventually the equilibrium price in b went up to $10/bushel. both countries are known to have equal number of corn producers and the market supply of corn is identical at all prices. this, combined with the fact that consumers in the two countries also have similar tastes and preferences, led the media to conclude that the price of corn in country a would soon be as high as $10/bushel. the new equilibrium price turns out to be below $10/bushel, what inferences can be drawn?

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.)

Lavage rapide is a canadian company that owns and operates a large automatic car wash facility near montreal. the following table provides data concerning the company’s costs: fixed cost per month cost per car washed cleaning supplies $ 0.70 electricity $ 1,400 $ 0.07 maintenance $ 0.15 wages and salaries $ 4,900 $ 0.30 depreciation $ 8,300 rent $ 1,900 administrative expenses $ 1,400 $ 0.03 for example, electricity costs are $1,400 per month plus $0.07 per car washed. the company expects to wash 8,000 cars in august and to collect an average of $6.50 per car washed. the actual operating results for august appear below. lavage rapide income statement for the month ended august 31 actual cars washed 8,100 revenue $ 54,100 expenses: cleaning supplies 6,100 electricity 1,930 maintenance 1,440 wages and salaries 7,660 depreciation 8,300 rent 2,100 administrative expenses 1,540 total expense 29,070 net operating income $ 25,030 required: calculate the company's revenue and spending variances for august.