Optimal wager on two games given probability and odds

If the player is infinately risk averse she should bet $x$ on $C$ and $100-x$ on $D$ where $x$ is determined by the equation \begin{eqnarray*} \frac{x}{2}\ast 7+x &=&\frac{100-x}{3}+100-x\rightarrow \\ x &=&\frac{160}{7} \end{eqnarray*} Then, if $C$ wins she will get a net profit of $\frac{160}{7}\frac{7}{2}+% \frac{160}{7}-100=2.8571.$

And if $D$ wins she will get a net profit of $\ \frac{100-\frac{160}{7}}{3}-(% \frac{160}{7})=2.\,857\,1$

Hence, there is a possibility to make a guaranteed profit of $% 2.\,8571$ for every $100$ invested. It is thus a good strategy if she had a credit card without limit.