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Math Help - Need help on probability question

  1. #1
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    Need help on probability question

    There are 5 men and 3 women in a room. Given probability for men with beard is 1/10.

    a) find the probability that there are three men with beard and two with no beard.
    Do i need to count three men with beard X two men with not beard? or only count for three men with beard?

    b)if two people are selected randomly from the people in the room, what is the probabiliy that both of them are men with beard?

    Any idea?
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  2. #2
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    Quote Originally Posted by eureka View Post
    There are 5 men and 3 women in a room. Given probability for men with beard is 1/10.
    a) find the probability that there are three men with beard and two with no beard.
    Find the probability of exactly three men having a bread (that implies other two doth not).
    To do that use binomial probability,
    5C3 (1/10)^3(9/10)^2

    b)if two people are selected randomly from the people in the room, what is the probabiliy that both of them are men with beard?
    What is probability of selecting two men?
    5C2/8C2
    That means the probability of selecting two men.
    What is probability of both having beards?
    (1/10)(1/10)=1/100
    Now multiply the two numbers you get for final answer.
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  3. #3
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    Probability

    Hi ThePerfectHacker

    Thanks for your help and sorry for double post, as i am new to forum and i would need to submit my work today.. therefore did wrong post... really sorry.

    would need your clarification for second question, does that mean that;

    5C2/8C2 = 5/14

    and follow by 5/14 * 1/100 = 1/280

    so the answer is 1/280, is that what you mean?

    Thanks for your assistant...
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  4. #4
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    Quote Originally Posted by eureka View Post
    Hi ThePerfectHacker

    Thanks for your help and sorry for double post, as i am new to forum and i would need to submit my work today.. therefore did wrong post... really sorry.

    would need your clarification for second question, does that mean that;

    5C2/8C2 = 5/14

    and follow by 5/14 * 1/100 = 1/280

    so the answer is 1/280, is that what you mean?

    Thanks for your assistant...
    5C2=10
    8C2=28
    Thus,
    10/28=5/14
    Now multiply by 100,
    1/280
    Yes.
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