Given:
Adam's locker has a password that consists of 4 non-repeated letters from A - Z.
To find:
The number of different passwords.
Solution:
Total number of letters from A - Z is 26.
So, the number of selecting a letter for first place is 26.
The passwords consists non-repeated letters. So, the remaining numbers is
.
The number of selecting a letter for second place is 25.
Similarly,
The number of selecting a letter for third place is 24.
The number of selecting a letter for fourth place is 23.
The total number of possible different passwords is:

Therefore, the total number of different passwords is 358800.