Two balls selected from a box containing 2 blue and 7 red balls. What is the probability that at least one ball is blue? ?

3 Answers

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  • 4 weeks ago

    5/12

  • Ash
    Lv 7
    1 month ago

    Another way of solving it....

    P(at least 1 blue ball) = 1 - P(no blue balls)

    P(no blue balls) = (₇C₂ * ₂C₀)/(₉C₂) = [7!/(2!*5!)]*1 /[9!/(2!*7!)] = 21/36 = 7/12

    P(at least 1 blue ball) = 1 - (7/12) = 5/12

  • 1 month ago

    1 - P(0 Balls Are Blue)

    1 - (7/9)(6/8) = 5/12

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