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Homework Help: Probability of receiving bonus

  1. Jul 25, 2014 #1
    1. The problem statement, all variables and given/known data
    please refer to the photo, can i redo the question in this way ?

    P( male receive, female not receive) +P( female receive , male not receive)

    ( (10/1000)x (170/999) ) + ( (470/1000)x (260/999) ) = 0.1393

    this is based on 'without replacement' is my concept wrong?

    2. Relevant equations

    3. The attempt at a solution

    Attached Files:

  2. jcsd
  3. Jul 25, 2014 #2


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    You are given that, of 360 male workers, "100 earn less than RM2000.00 a month".
    In your calculation for b, you use a probability of .10. That would be 100/10000, the probability that a randomly chosen worker is male and earns less than RM2000.00 a month. But you are told that a male and female worker are chosen so you should not include the probability a worker chosen is male. The probability the male worker earns less than RM2000.00 a month is 100/360, not 100/1000.
  4. Jul 25, 2014 #3
    so the ans would be ( (260/350) x (470/640)) + ( (100/360) x (170/640 )) = 0.604 ?
  5. Jul 25, 2014 #4


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    As a curiosity, the problem as stated is not solvable as the workers earning exactly 2000.00 are included in the group earning a month's salary as bonus and thus will also get a 2000.00 bonus. We are not given the number of such workers.
  6. Jul 25, 2014 #5
    here's another part of this question,

    find the probability of the three doctors selected . the correct working would be (20C3 X15C1)/35C4 = 0.327

    can i do in this way? P(DDDE) + P(EDDD) + P(DEDD) +P(DDED) =
    ( (20/35) x (19/34) x (18/35) x (15/32) ) x 4 = 0.327

    Is my concept wrong? D=doctor E=engineer
  7. Jul 27, 2014 #6
    by doing this ( (260/350) x (470/640)) + ( (100/360) x (170/640 )) = 0.604 ,
    i assume that P(male receiving bonus, girl not receiving bonus) + P(girl receiving bonus , boy not receiving bonus)

    why there's also probability that girls picked first and not receiving bonus , then male receiving bonus is picked after this for P(male receiving bonus, girl not receiving bonus) ? and the same thing goes to P(girl receiving bonus , boy not receiving bonus) ... why the sequence is not important ?

    why cant i do in this way? ( (260/350) x (470/640)x2) + ( (100/360) x (170/640 )x2) , but by doing so my ans is more than 1 , which is indeed not correct.
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