8. [7] Alice rolls two octahedral dice with the numbers $2,3,4,5,6,7,8,9$. What's the probability the two dice sum to 11 ?
Answer: $\quad \frac{1}{8}$ No matter what comes up on the first die, there is exactly one number that could appear on the second die to make the sum 11 , because 2 can be paired with 9,3 with 8 , and so on. So, there is a $\frac{1}{8}$ chance of getting the correct number on the second die.