平狄克的微观上有两道习题，汽油退税后和食品退税后消费者的境况变好了还是变差了，答案给的均是变好了。但是书上案例是变差了。我觉得答案有点问题，下面是食品那道题。
Suppose the income elasticity of demand  for food is 0.5 and the price elasticity of demand is –1.0.  Suppose also that Felicia spends $10,000 a year on food, the price of food is $2, and that her income is $25,000.
a.  If a sales tax on food caused the price  of food to increase to $2.50, what would happen to her consumption of food?  
b.  Suppose that Felicia gets a tax rebate of $2500 to ease the effect of the sales tax.  What would her consumption of food be now?
c.  Is she better or worse off when given a rebate equal to the sales tax payments?  
最后一问的答案：Felicia is better off after the rebate.  The amount of the rebate is enough to allow her to purchase her original bundle of food and other goods.  Recall that originally she consumed 5000 units of food.  When the price went up by fifty cents per unit, she needed an extra (5000)($0.50) = $2500 to afford the same quantity of food without reducing the quantity of the other goods consumed.  This is the exact amount of the rebate. However, she did not choose to return to her original bundle.  We can therefore infer that she found a better bundle that gave her a higher level of utility.  
我觉得斜体部分是有问题的，收税后Felicia食品的消费量已经达不到5000了，因此其退税额也应小于2500，因此她实际上无法再承担原来的商品组合了，即境况变差了。不知道我想的对不对。如果有谁能对退税的福利变化给出一个很很确定的答案，我感激不尽啊。所有回帖的人我都要说声谢谢哈。