问题如下图：
选项：
A. 
B. 
C. 
D. 
解释：
debt =risk free-put. 为什么risk free 是107
NO.PZ2016082405000104 问题如下 Given the fc llowing parameters for a firm, whis the value of the firm's equity? • Asset value of $180. • Risk-free rate of 5%. • $100 pvalue with a 7% coupon, maturing in one year. • A Europeput option worth $1.50 on the firm's assets with a strike priequto the favalue of bt. $74.00. $74.52. $79.20. $79.72. The film’s equity ccalculateEt = At - . We cvalue using the Merton mol: = -rT - (Europeput value with strike = $107 x e-0.05*1 - $1.50 = $100.28 We cthen calculate Et: Et = At - = $180 - $100.28 = $79.72. 请问老师这道题是不是有点问题，莫顿模型里假设债券是零息债券，put option执行价等于bt的面值，但是这道题有了coupon put option的执行价还是只等于面值，不是就和模型不符了吗？ x
NO.PZ2016082405000104 $74.52. $79.20. $79.72. The film’s equity ccalculateEt = - . We cvalue using the Merton mol: = -rT - (Europeput value with strike = $107 x e-0.05*1 - $1.50 = $100.28 We cthen calculate Et: Et = - = $180 - $100.28 = $79.72. 老师，权益等于资产减去负债，为啥期权费也算进去呢？
请问这里公式中的代表的是最后到期时的面值吗？
请问为什么不能先算出EL=PUT*e^0.05，用Asset=180-EL，bt就还是107/e^0.05
