Think of the golfers as the boxes. So, to distribute r distinct objects into n different boxes you can use
3 balls each.
so suppose we give them out in order
we have \binom{12}{3} possibilities of balls for the first guy
then \binom{9}{3} possibilities of balls for the second guy
then \binom{6}{3} for the third
and whatever is left over for the last guy
this gives ways
but we have not acounted for the order in which we distributed the balls so each distrubtion of the balls is repeated times.
giving a final answer of
And what would be the solution if the balls are indistinctive?
Namely, I have a similar problem. In how many ways can one put n blank sheets in k drawers, whereas a drawer can be empty?
e.g. 100 sheets, 3 drawers
d1 d2 d3
100 0 0
0 100 0
23 45 32
etc.
Thanks!