i1brich 发表于 2012-9-9 23:05 
华语的还真不会做。可以翻译英文吗?
马来西亚华人?
A stock is trading at 30. Its continuous dividend yield is 8%.
1. The risk free rate (continuous) is 4%
2. The prices of 5 one-year European calls with different strikes on the stock are listed below
K c
40 2.12
50 1.91
60 0.71
70 0.21
80 0.00
3. There is a one-year European put, whose strike is one of the K in the table above. The put holder may choose to exercise the put immediately (????) or to exercise at maturity.
What is the minimum strike for the put holder to exercise immediately?