WEBVTT

1
00:00:00.000 --> 00:00:04.725
Here is the problem: How many ways can you arrange 5 of 5 items in order?

2
00:00:05.175 --> 00:00:07.915
Permutations nPr (order matters).

3
00:00:08.715 --> 00:00:10.480
Use the permutation formula.

4
00:00:10.930 --> 00:00:14.471
Cancel 0! to leave the first 5 factors of 5!

5
00:00:15.271 --> 00:00:19.160
So the answer is P(5, 5) equals 120.

6
00:00:19.610 --> 00:00:24.242
There are 120 ordered arrangements of 5 items chosen from 5.

7
00:00:25.042 --> 00:00:34.109
Check: P(5, 5) equals C(5, 5) times 5! equals 1 times 120 equals 120.