Answer to Question 1
They are all designed to induce firms and households to weigh the social costs of their actions against their benefits. The actual size of the external cost/benefit depends on the reaction of households and firms to the incentives provided by the taxes, subsidies, and rules. That is the principle limitation.
Answer to Question 2
A tradeoff reflects the point that when someone gets one thing, something else must be given up. What is given up is the opportunity cost of whatever is obtained. Three examples of tradeoffs that are common to students include: a) When a student sleeps in rather than going to his or her early morning economics class, the student trades off additional sleep for study time. The opportunity cost of the decision is a lower grade on the exam. b) When a student running late for class parks his or her car illegally, the student trades off saving time for the risk of a ticket. The potential opportunity cost of the decision is the goods and services that cannot be purchased if the student receives an expensive parking ticket. c) A student trades off higher income by spending time during the day working at a part-time job for less time spent at leisure time and study. The opportunity cost for the higher income is less leisure and lower grades in classes.
Examples of contraceptive methods
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Three days after the Boston Marathon explosion, the FBI released this photograph that had been taken
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