Question

    A box holds a total of 'p' purple balls and 5 silver

    balls. Two balls are drawn sequentially without replacement. The probability that both selected balls are purple is given as 3/7 . Determine the value of 'p'.
    A 10 Correct Answer Incorrect Answer
    B 12 Correct Answer Incorrect Answer
    C 11 Correct Answer Incorrect Answer
    D 14 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ,

    p*(p-1)/ [(p+5)*(p+4)] = 3/7 By using optional method, (10*9)/ (15*14) = 90/210 = 3/7 p = 10

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