Which of the following is an example of a positive externality of air travel?

Fertilizer runoff from farms can cause ocean “dead zones” near the mouths of rivers. Among other things, the existence of these zones reduces the catch of fishermen in the area. Suppose that corn farms are one source of fertilizer runoff. The lost economic surplus associated with the competitive market equilibrium for corn is 

If she does not incur any fixed costs, what is Cary’s total profit?

Suppose that Cary’s Car Wash is the only car wash in its suburb and faces the following demand schedule for car washes per hour. 

Which of the following scenarios is least likely to involve market failure due to the existence of private information?

Which of the following statements best describes a perfectly competitive market?