来源:98年北大企管
Q: Toby Talkalot subscribes to a local phone service that changes a fixed fee
of $10 per month and allows him to place as many local phone calls as he
likes without further charge. Let good 1 be an aggregate of commodities
other than local phone use and let good 2 be local phone use.
(Measure good 1 on the horizontal axis and good 2 on the vertical axis.)
On Monday, Toby didn't use the telephone at all. The slope m of his
indifference curve at the consumption bundle he chose on Monday was
A)positive
B)less than or equal to 0
C)0
D)greater than 0
E)negative
补习班给的答案是A(但另有详解写E)
A的解释是由於纵轴的室内电话费率是0 因此Toby面对的预算限制式为垂直线
若他在星期一的最适选择是角解横轴商品 表示此时无异曲线一定是正斜率
选E的详解表示:虽然星期一没有使用~但费用已缴~无论有没有使用电话~都视为已购买
我的想法是:若把电话费率放在纵轴 那他星期一没有使用的确可看做价格下跌至无穷
但为什麽角解横轴一定表示无异曲线是正斜率呢?
有请高手解答了!谢谢!!
有在研究所问题板问过 有板友说Varian的课本有这一题 而答案给C
想请问看看到底要怎麽解释呢? 现在有三个版本啦...QQ
※ 编辑: scodowying 来自: 111.249.192.166 (07/27 00:36)