distributing z different objects among k people almost evenly We have z objects (all different), and we want to distribute them among k people ( k < = z ) so that the distribution is almost even.
i.e. the difference between the number of articles given to the person with maximum articles, and the one with minimum articles is at most 1.
We need to find the total number of ways in which this can be done
for example if there are 5 objects and 3 people the number of such ways should be 90.
I am not sure how we get this value.

As k is always less than z; 
First choose k elements from z; distribute it one for each person.
Then the remaining objects for your condition to be true;
Lets call a(1) = z-k;
Again repeat the process [n is the number of cycles]
till a(n) = z-n*k < k
Then distribute the remaining; Randomly. one person will only get one
This way the difference between the number of articles given to the person with maximum articles, and the one with minimum articles is at most 1.
