A hacker is trying to guess someone's password. The hacker knows (somehow) that the password is 13 characters long, and that each character is either a lowercase letter, (a, b, c, etc), an uppercase...

A hacker is trying to guess someone's password. The hacker knows (somehow) that the password is 13 characters long, and that each character is either a lowercase letter, (a, b, c, etc), an uppercase letter (A, B, C, etc) or a numerical digit (0, 1, 2, 3, 4, 5, 6, 7, 8, or 9). Assume that the hacker makes random guesses.


What is the probability that the hacker guesses the password on his first try? Enter your answer as a decimal or a fraction, not a percentage.