Probability of each combination with repetition
It looks like trivial problem but I cannot solve it.
I have M baskets and N balls. I can choose one of the baskets randomly and put a ball into the chosen basket.
I'm just interested in combination. So in three baskets with 5 balls,
(1) (1) (3)
(1) (3) (1)
(3) (1) (1)
above combinations are same for me.
I just want to know the probability of each combinations. I know that all possible combination can be represented by combination with repetition.
But I do not know that how many cases of each combinations are existed.
Any helps are appreciated!!!
Thanks in advance!