Economic Investment:

The isoquants for inputs that are perfect substitutes for one another consist of a series of:

a. right angles b. parallel lines c. concentric circles d. right triangles e. none of the above

Economists believe that people who sit through bad music concerts likely do so because:

A. they do not ignore the sunk cost involved. B. they undervalue the opportunity cost of their time. C. they don't accurately consider what else they could be doing with their time. D. All of these are true.