00:01
As in this problem, we are told that there is a group of nine men and you're selecting four person committees, four chair committees.
00:06
And it's basically asking us how many ways can we choose four chair committees such that one person is always on the committee.
00:13
If one person is always on the committee, then you have no choice.
00:16
That person has to be on there.
00:18
So in a sense, for the four spots that you're given, you're already taking up one spot with a man.
00:27
One spot with a man.
00:28
And that leaves eight months.
00:30
Men open for the remaining three spots.
00:34
So basically what you're doing is you're choosing three men from these eight men...