Determine the number of ways in which 5 prizes can be distributed among 4 students.
Suppose there were no restrictions whatsoever and the problem simply said "How can you distribute k prizes among p students?".
For each prize, there are p possibilities for the recipient of that prize. In total, that means there are p⋅p⋅.....⋅p (with k copies of p in the product) possible ways to assign the prizes. This is the pk part.
Or, we can say. This is a type of “Different to Different” question.
5 prizes can be distributed among 4 students in 45 ways.