问答题 社会保障体系向工人征税并给老年人津贴。假设国会既增加税收又增加津贴。为了简单起见，假设国会宣布，这种增加只持续一年。
   a．你认为这种变动会如何影响经济?(提示：考虑年轻人和老年人的边际消费倾向。)
   b．你的回答取决于各代人之间是否有利他主义的联系吗?
   The Social Security system levies a tax on workers and pays benefits to the elderly. Suppose that Congress increases both the tax and the benefits. For simplicity, assume that the Congress announces that the increases will last for one year only.
   a．How do you suppose this change would affect the economy? (Hint: Think about the marginal propensities to consume of the young and the old.)
   b．Does your answer depend on whether generations are altruistically linked?