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Math Help - A possible permutations/combination problem

  1. #1
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    Question A possible permutations/combination problem

    Suppose that your computer password must contain four characters, must begin with a letter, and may contain digits and letters only. How many different passwords can you create?

    I've been learning permutations and combinations at the same time, does this count as a permutation problem? I don't think it does, and I'm not sure how to approach this
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  2. #2
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    Re: A possible permutations/combination problem

    Hey chopper07.

    You are better off thinking of it using first principles and not as a "A or B type problem".

    When things are independent, you multiply.

    How many combinations di you have for each character? Is each character independent from all the others?
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  3. #3
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    Re: A possible permutations/combination problem

    what do you mean when you ask if each character is independent?

    so do I multiply 26 x number of digits/letters?
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  4. #4
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    Re: A possible permutations/combination problem

    Independence means that if you change one thing, it doesn't affect the others in any way.
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    Re: A possible permutations/combination problem

    yes each character is independent
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  6. #6
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    Re: A possible permutations/combination problem

    So multiply the choices of each character to get the total number for all characters.
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