A box contains 5 black and 2 white balls. 2 balls are drawn without replacement. Find the probabilit

Discussion in 'Calculator Requests' started by math_celebrity, Jan 17, 2021.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    A box contains 5 black and 2 white balls. 2 balls are drawn without replacement. Find the probability of drawing 2 black balls.


    First draw probability of black is:
    Total Balls in box = Black balls + white balls
    Total Balls in Box = 5 + 2
    Total Balls in Box = 7

    P(Black) = Black Balls / Total balls in box
    P(Black) = 5/7

    Second draw probability of black (with no replacement) is:
    Total Balls in box = Black balls + white balls
    Total Balls in Box = 4 + 2
    Total Balls in Box = 6

    P(Black) = Black Balls / Total balls in box
    P(Black) = 4/6
    Using our fraction simplifier, we see that 4/6 is:
    2/3

    Since each event is independent, we can multiply them to find the probability of drawing 2 black balls:
    P(Black, Black) = 5/7 * 2/3
    P(Black, Black) = 10/21

     
    Last edited: Jan 2, 2024

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