Question

The Greek alphabet contains 24 letters. How many fraternity names with Greek letters can be formed if each fraternity name contains 3 letters and repetition of letters is not permitted?
(So for permutations, usually you can just multiply it like three times. so normally you would do it like 24*24*24 and that equals 13,824 but that is not the correct answer, the correct answer is 12,144. How?)

Answer 1

It says “no repetition is allowed”
So for the first letter - 24 letters allowed
For the second letter - 1 letter had already been used, so 23 letters remain
Last letter - 22 letters remain

So 24 * 23 * 22