00:01
In your question, you're asked for how many permutations of size 3 that we can make from the vowels a, e, i, o, u without repeating letters.
00:14
So what we're looking at is an arrangement.
00:17
Permutation stands for arrangements, meaning the order matters.
00:26
So for example, if i had a e i, that counts as one permutation, and e a i, even though it uses the same letters, it's a different arrangement.
00:39
We would count that as another permutation.
00:43
Now the key to this question here is that we are not allowed to repeat.
00:48
So when we look at how many letters we could choose for the first letter, there are five that we could choose from...