00:01
Okay, so this one says to use a certain cache machine, you need personal identification code.
00:06
If each pic contains consists of two letters followed by one of the digits from one to nine, such as aq7 or bb3, or one letter followed by two digits, how many different pics can be assigned.
00:20
Okay, so first of all, we know that there are two scenarios.
00:23
One is if there is a letter, letter, digit, and the second is if it was let.
00:30
Letter, digit, digit.
00:32
So then for the number of letters, we know there are 26 possibilities, because there's 26 letters in the alphabet.
00:39
So 26 times 26 again, times 9...