1. **State the problem:**
We want to find the probability that Clara wins exactly one of the two games.
2. **Identify probabilities from the tree:**
- Probability of winning Game 1: $\frac{9}{11}$
- Probability of losing Game 1: $\frac{2}{11}$
- Probability of winning Game 2: $\frac{9}{11}$
- Probability of losing Game 2: $\frac{2}{11}$
3. **Formula for exactly one win:**
The event "exactly one win" means either:
- Win Game 1 and Lose Game 2, or
- Lose Game 1 and Win Game 2.
So,
$$P(\text{exactly one win}) = P(W_1 \cap L_2) + P(L_1 \cap W_2)$$
4. **Calculate each probability:**
- $P(W_1 \cap L_2) = P(W_1) \times P(L_2) = \frac{9}{11} \times \frac{2}{11} = \frac{18}{121}$
- $P(L_1 \cap W_2) = P(L_1) \times P(W_2) = \frac{2}{11} \times \frac{9}{11} = \frac{18}{121}$
5. **Add the probabilities:**
$$P(\text{exactly one win}) = \frac{18}{121} + \frac{18}{121} = \frac{36}{121}$$
6. **Simplify the fraction:**
$$\frac{36}{121} = \frac{\cancel{36}}{\cancel{121}} \text{ (no common factors to cancel)}$$
So the probability is $\frac{36}{121}$.
**Final answer:**
$$\boxed{\frac{36}{121}}$$
Exactly One Win 386Cfd
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