这是一份KCL伦敦大学学院 5QQMB201作业代写的成功案
Step 1. Calculate the opportunity cost of capital.
$$
\begin{aligned}
r &=r_{D} D / V+r_{E} E / V \
&=.09(.3)+.15(.7)=.132, \text { or } 13.200
\end{aligned}
$$
Siep 2. Calculate the new costs of debt and equity. The cost of debt will be higher at $50 \%$ debt than $30 \%$. Say it is $r_{D}=.095$. The new cost of equity is:
$$
\begin{aligned}
r_{E} &=r+\left(r-r_{D}\right) D / E \
&=.132+(.132-.095) 50 / 50 \
&=.169, \text { or } 16.99
\end{aligned}
$$
Siep 3. Recalculate WACC.
$$
\begin{aligned}
\text { WACC } &=r_{D}\left(1-T_{d}\right) D / V+r_{E} E / V \
&=.095(1-.35)(.5)+.169(.5)=.1154, \text { or about } 11.5 \%
\end{aligned}
$$
5QQMB201 COURSE NOTES ：
upside change – downside change
In the case of Google stock:
$$
p=\frac{.015-(-.25)}{.333-(-.25)}=.4543
$$
We know that if the stock price rises, the call option will be worth $\$ 143.33$; if it falls, the call will be worth nothing. Therefore, if investors are risk-neutral, the expected value of the call option is:
[Probability of rise $\times 143.33]+[(1-$ probability of rise $) \times 0]$
$$
\begin{aligned}
&=(.4543 \times 143.33)+(.5457 \times 0) \
&=\$ 65.11
\end{aligned}
$$
And the current value of the call is:
$$
\frac{\text { Expected future value }}{1+\text { interest rate }}=\frac{65.11}{1.015}=\$ 64.15
$$