Question

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.

Answer 1

Answer:

$0.5^{-23}$

Explanation:

OK so there is 26 (number of the lower case letters) + 26 (number of the upper case letters) + 10 ( the number of numerical digits) = 62 types of possibilities for each charater in the password, so there should be (62^13)=200028539268669788905472=2*(10^23) types of possible combinitions in total.

If the hacker is so lucky that he got it on his first try, that would be only one of the possible senarios, so the odd is 1/(2*10^23)=0.5*(10^-23)