If a project costs $600 today and returns $630 next year, the highest interest rate at which the project should still be undertaken is five percent

Suppose that at a given level of output, a perfectly competitive firm charges a price of $12 and has average total costs of $10 . If its economic profit is $20,000 . then it must be producing:

a. 40,000 units of output. b. 20,000 units of output. c. 30,000 units of output. d. 10,000 units of output. e. 50,000 units of output.

Alex's production is worth $60, Harry's is worth $40, Rob's is worth $40, and Julia's is worth $55 . They decide to combine their resources and produce together. For this to be a superadditive game, which of the following conditions must hold?

a. They should be able to produce more in groups of two than what they can produce together. b. Their combined production must exceed the total they can individually produce. c. Their resources must be perfect substitutes. d. Their resources must be perfect complements.