00:01
Let's talk about the difference between a combination and a permutation.
00:04
In a combination, order does not matter.
00:08
So here, selecting events, a, b, and c is the same as selecting events.
00:13
B, a, then c, all that matters is that you are selected.
00:16
Whereas a permutation, order does, in fact, matter.
00:21
So then selecting events, a, b, and c is different than b, than c, since the order that was selected matters.
00:27
So let's say 50 people purchase raffle tickets and three are selected.
00:32
If each prize is the same, does the order matter? no, and this first one, order does not matter.
00:37
So it's going to be 50, choose three.
00:39
This will be 50 factorial over 3 factorial.
00:43
50 minus 3 is 47 factorial.
00:45
So expanding this out, 50 times 49 times 48 times 47 factorial, all over 47 factorial.
00:53
And i can expand out 3 factorial...