Suppose a poverty program has a basic benefit of $10,000, and a family can earn up to $20,000 before losing all welfare benefits. The marginal tax rate is ________ percent.

Consider the following pieces of information:

a. According to Bonnie Reyes, president and chief operating officer of Better Investing, a national organization of investment clubs, women have traditionally made up about 60 percent of the membership of investment clubs. By contrast, less than a third of team-managed mutual funds on Wall Street have even one woman on the management team. b. Research conducted by professors E. Brooke Harrington and Max Planck concluded that mixed investment clubs, on average, outperformed the typical single-sex investment club. c. The lack of gender diversity in Wall Street could be influenced by its reputation, according to professor Harrington, "for being inhospitable to women." Source: Michael Hulbert, "Strategies: At some Funds, a Gender Communications Gap," The New York Times, October 7, 2007, Sunday Money, page 5. The information presented is an example of A) a negative feedback loop. B) marginal productivity theory. C) the absence of comparable worth. D) economic discrimination.

Fred, a poor college student, states: "I eat tuna sandwiches five times a week. When I graduate and get a real job, I will never purchase tuna again." Is Fred planning on breaking the law of demand?