There are different books to be distributed among three students, with each student receiving at least book and at most books. The number of different distribution methods is .
Problem 165
Official solution
Analysis
This problem involves the combined application of combinations and permutations. We can first determine that the distribution can be divided into , , and books.
Step-by-step solution
1. First, we will find the number of ways to choose books out of for the first two students who will receive books each. This can be calculated using the combination formula: .
2. Next, we have books remaining (as the first two students have already received their books), and we will choose books for the second student who will receive books. Again, using the combination formula: .
3. Now, we have considered the distribution of books to the first two students receiving books each. However, since there are two students receiving the same number of books, we need to divide the result by the number of arrangements of these students ().
4. Finally, there is only book left, and it will be given to the last student. There are ways to choose this last student.
5. Combining these results, we find the total number of distribution methods:
Therefore, there are different methods to distribute the books.