There are 5 red and 4 black balls in a box. If you pick out 2 balls without replacement, what is the

Discussion in 'Calculator Requests' started by math_celebrity, Aug 1, 2017.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    There are 5 red and 4 black balls in a box. If you pick out 2 balls without replacement, what is the probability of getiing at least one red ball?


    First list out our sample space. At least one means 1 or 2 red balls, so we have 3 possible draws:
    1. Red, Black
    2. Black, Red
    3. Red, Red

    List out the probabilities:
    1. Red (5/9) * Black (4/8) = 5/18
    2. Black (4/9) * Red (5/8) = 5/18
    3. Red (5/9) * Red (4/8) = 5/18
    Add these up:
    3(5)/18 = 5/6
     

Share This Page