The Jeans Store sells 7 pairs of jeans per day when it charges $100 per pair. It sells 8 pairs of jeans per day at a price of $90 per pair. The marginal revenue of the eighth pair of jeans is

The economic way of thinking assumes

A) people act selfishly. B) people act altruistically. C) people act to promote the projects in which they are interested. D) people do not act at all; they merely react to the environment around them.

Economists generally assume

A) individuals act strictly in the public interest. B) individuals are never concerned with the interests of other people. C) individuals rarely promote the projects in which they are interested. D) none of the above.