Question

5. Suppose a password requires three distinct letters. Find the number of permutations for the three letters in the code if the letters may not be repeated.

Answer 1

There are 15600 ways to pick a password

Explanation:

We have 26 possibilities to pick a letter. So, we have 26 possibilities for the first component of the password. The second letter should be different from the first one, so we have one less possibility, giving us a total of 25, and for the third letter we have 24.

This gives us 26*25*24 = 15600 ways of picking a password.