New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    Directions(Q.71 -75) : In each of the following questions, a question and two statements I and II are given. You have to decide whether the date given in the statements are sufficient to answer the question or not.

    What is the probability of getting two white balls from

    a box containing only white and blue balls? Statement I : There are total 72 balls in the box. Statement II : The probability of the first ball being white is 1/12.
    A If the data in statement I alone is sufficient to answer the question. Correct Answer Incorrect Answer
    B If the data in statement II alone is sufficient to answer the question. Correct Answer Incorrect Answer
    C If the data either in statement I alone or statement II alone are sufficient to answer the question. Correct Answer Incorrect Answer
    D If the data given in both I and II together are not sufficient to answer the question. Correct Answer Incorrect Answer
    E If the data in both the statements I and II together are necessary to answer the question. Correct Answer Incorrect Answer

    Solution

    From statement II : Probability of second ball being white cannot be known. If we use both statements: Since total 72 balls are there and probability of first being white is 1/12, it can happen only when there are 12 white balls in the box to make the first probability as 12/72 = 1/6. So we can know that probability of second ball being white is 1/5. And then the probability can be found.

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