00:03
We have five chairs, and in the first part, we have two people.
00:06
And if we pick the chairs that they're going to be selected to seat, it doesn't matter the order in which we pick them, so five choose two.
00:15
So there are 10 ways to pick the two chairs, but now we need the people to sit down, and the order in which they sit is two times one.
00:24
So there are 20 different ways if we have two people.
00:28
Now, what happens if we have three people? if we have three people, now we need to select those three chairs.
00:35
The order in which you select the chairs, it doesn't matter if i say one, two, three, or three, two, one, you just want a group of three chairs.
00:42
So that's ten.
00:43
But now there are three factorial ways to seat those people down.
00:48
And three factorial is six, so we would have 60.
00:52
So now we want to go with four people...