Math Problem Statement

A company has its employees choose a password which consists of 9 characters: 3 letters, followed by 2 symbols, followed by 4 digits. There are a total of 11 symbols that the employees can choose from. Letters, symbols and digits can be repeated. How many possible passwords are there?

Solution

To calculate the total number of possible passwords, we need to multiply the number of choices for each section of the password.

  1. Letters (3 letters): There are 26 letters in the alphabet, and since letters can be repeated, each of the 3 letters has 26 possible choices. So, the total number of ways to choose the 3 letters is:

    26×26×26=26326 \times 26 \times 26 = 26^3

  2. Symbols (2 symbols): The company allows the use of 11 different symbols, and symbols can also be repeated. So, the total number of ways to choose the 2 symbols is:

    11×11=11211 \times 11 = 11^2

  3. Digits (4 digits): There are 10 digits (0 through 9), and digits can be repeated. So, the total number of ways to choose the 4 digits is:

    10×10×10×10=10410 \times 10 \times 10 \times 10 = 10^4

Finally, to find the total number of possible passwords, multiply the results from each part:

263×112×10426^3 \times 11^2 \times 10^4

Now, calculating:

263=26×26×26=17,57626^3 = 26 \times 26 \times 26 = 17,576 112=11×11=12111^2 = 11 \times 11 = 121 104=10,00010^4 = 10,000

So, the total number of possible passwords is:

17,576×121×10,000=2,125,696,00017,576 \times 121 \times 10,000 = 2,125,696,000

Thus, there are 2,125,696,000 possible passwords.


Would you like a breakdown of any specific part or further details? Here are some related questions you could explore:

  1. What if symbols couldn't be repeated?
  2. What if letters couldn't be repeated?
  3. How would the number of passwords change if the number of digits were reduced to 3?
  4. What is the probability of guessing a password correctly on the first try?
  5. How does the length of a password affect security?

Tip: Increasing the number of unique symbols, letters, or digits significantly boosts the total number of possible combinations, enhancing password security.

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Math Problem Analysis

Mathematical Concepts

Combinatorics
Probability
Counting Principles

Formulas

Total combinations = (number of choices for letters) × (number of choices for symbols) × (number of choices for digits)
Letters: 26^3
Symbols: 11^2
Digits: 10^4

Theorems

Multiplication principle of counting

Suitable Grade Level

Grades 10-12