11. Marco owns two dice. One of them is a regular game die, with faces numbered from 1 to 6. The other is a special die, which has two faces with the number 3, one face with the number 4, and three faces with the number 6. By rolling both dice together, what is the probability that the sum of the two numbers rolled is equal to 10?
(A) $2 / 9$
(B) $1 / 18$
(C) $1 / 9$
(D) $1 / 6$
(E) $1 / 12$
(11) The correct answer is $(C)$.

If the score achieved by the special die is 3, it is not possible for the sum of the two scores to be 10. If, however, the score of the special die is 4 or 6, there is exactly 1 score out of 6 of the normal die for which the sum of the two scores is 8. Since the probability of achieving 4 or 6 with the special die is $\frac{4}{6}$, the probability that the sum is 10 is therefore $\frac{4}{6} \cdot \frac{1}{6}=\frac{1}{9}$.

Question proposed by Sandro Campigotto.