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    Question

    A box contains Z black balls and

    7 white balls. If two balls are drawn at random, one after another without replacement, and the probability of drawing both black balls is 5/11 , find the value of Z.
    A 10 Correct Answer Incorrect Answer
    B 11 Correct Answer Incorrect Answer
    C 13 Correct Answer Incorrect Answer
    D 14 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ, Using the optional method:

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