NO.PZ2018091705000044
问题如下：
Peter is 79 years old and his wife Lucy is 68 years old. They would like to maintain their living standards with spending requirement of $300,000 in real terms.
Assuming inflation rate is 2% and nominal risk-free rate is 4%. The survival probabilities for the next three years are listed in the following table:
The probability that either Peter or Lucy will survive over the year 1 is:
选项：
A. 0.9197
B. 0.9989
C. 0.9355
解释：
B is correct.
考点：Estimating core capital with mortality tables
解析：表格给出的是每个人每年的存活概率，我们需要计算出至少有一个人存活的概率，即联合概率（joint survival）。
所以第一年 P (joint survival) =0.9355+0.9831-0.9355×0.9831=0.9989
我觉得李老师的那个方法有点难理解，就用1-两个都死了的概率就好了