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Math Help - Probability check

  1. #1
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    Probability check

    I came across this task, and I could not solve it furthermore.
    Can anyone check my equation and help me solve it?

    -The probability to succeed in a random test is 0.8. It's known that if N people attending to the test the probability that all of them will succeed is 0.4096.
    A- Find N.

    I was only able to do this equation (Bernouli's table)

    (N/K)*(0.8)^k*(0.2) ^n^-K=0.4096
    Can anyone help me solving furthermore with this equation please.
    that's ^n-k
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  2. #2
    MHF Contributor alexmahone's Avatar
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    Quote Originally Posted by Mathematicsfan View Post
    I came across this task, and I could not solve it furthermore.
    Can anyone check my equation and help me solve it?

    -The probability to succeed in a random test is 0.8. It's known that if N people attending to the test the probability that all of them will succeed is 0.4096.
    A- Find N.

    I was only able to do this equation (Bernouli's table)

    (N/K)*(0.8)^k*(0.2) ^n^-K=0.4096
    Can anyone help me solving furthermore with this equation please.
    that's ^n-k
    (0.8)^N=0.4096

    Can you solve for N?
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  3. #3
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    No, I don't know I tried desperately.
    can you guide me ?
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  4. #4
    MHF Contributor alexmahone's Avatar
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    Quote Originally Posted by mathematicsfan View Post
    no, i don't know i tried desperately.
    Can you guide me ?
    (0.8)^N=0.4096

    (0.8)^N=(0.8)^4

    Find N.
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  5. #5
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    How did you get 4? cause that's the answer .
    and where did the 0.2 ^n-k go ? and N\K ?
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  6. #6
    MHF Contributor alexmahone's Avatar
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    Quote Originally Posted by Mathematicsfan View Post
    How did you get 4? cause that's the answer .
    and where did the 0.2 ^n-k go ? and N\K ?
    This is a very simple question which does not require the use of Bernoulli's tables. You're probably overthinking it.
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  7. #7
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    then i don't know how to solve it.
    can you help me with what to do next ?
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  8. #8
    MHF Contributor alexmahone's Avatar
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    Quote Originally Posted by Mathematicsfan View Post
    then i don't know how to solve it.
    can you help me with what to do next ?
    I solved it for you in post #4. N=4.
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  9. #9
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    lolllllllllllll I got it lollll
    this is so easy wow.w
    I just had to play with the Powers /
    lol thanks a lot
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