Problem 3. The faces of a die are numbered from 1 to 6. However, the weight of the die is distributed unevenly, and the probability of the number $k$ appearing is directly proportional to $k$. The die is rolled twice in a row. What is the probability that the sum of the numbers rolled will be 7? If necessary, round your answer to 0.01.
Answer: $8 / 63 \approx 0.13$.