NO.PZ2020011303000165
问题如下：
A six-month bond that pays coupons at the rate of 5% per year is currently worth 100.5. What is the six-month discount factor?
解释：
The discount factor is 100.5/(100 + 2.5) = 0.980488.
题目问：一个6个月的债券，coupon rate是5%，现在价值100.5，求discount factor
6个月的discount factor is 100.5/(100 + 2.5) = 0.980488.
题目说coupon是5%per year 那就是半年给2.5 然后已知PV 为什么要用100+2.5 不是100.5+2.5？又没有告诉pv是100
