If this guy doesn't use the letter m, then the first and second characters of the password could be any of the 25 remaining letters. Â So, the number of possible combinations of 2 letters is 25 times 25, or 625. Â
If he doesn't use the digit 0, how many digits are left to choose from?
The first 2 characters of the password will be letters; after that there come four digits. Â How many different combinations of 4 digits are there if 0 is not used?
To obtain the final result, mult. together that 625 and the number of possible combinations of digits just found above.