Question

A spyware is trying to break into a system by guessing its password. It does not give up until it tries 1 million different passwords. What is the probability that it will guess the password and break in if by rules, the password must consist of

Answer 1

Answer:

$Probability = 0.006033$

Step-by-step explanation:

Given

$Tries = 1000000$

Required

Determine the probability of 6 different lower case letters (Question continuation)

There are 26 lower case letters.

The first can be any of letters 26

The second can be any of letters 26 - 1

The third can be any of letters 26 - 2

The fourth can be any of letters 26 - 3

The fifth can be any of letters 26 - 4

The sixth can be any of letters 26 - 5

Number of selection is:

$Selection = 26 * (26 - 1) * (26 - 2) * (26 - 3) * (26 - 4) * (26 - 5)$

$Selection = 26 * 25 * 24 * 23 * 22 * 21$

$Selection = 165765600$

The probability is:

$Probability = \frac{Tries}{Selection}$

$Probability = \frac{1000000}{165765600}$

$Probability = 0.00603261472$

$Probability = 0.006033$ --- approximated