A store has four open checkout stands. Find the number of different ways that six customers can line up at these stands.
The way I did this (stars and bars):
Since there are 4 stands, I need to insert 3 dividers among these 6 people to make 4 groups.
Thus, I have 6+3=9 slots and 3 dividers to place.
9 choose 3 is 84.
Where am I wrong?
Other answers I have tried: 21 (84/4), 120 (10 choose 3), 165 (11 choose 3), 35 (7 choose 3)
Me again, I closed the window so I can't edit.
Using a Java program, I bashed it and found 56. That, too, is wrong.