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

    Question

    John is answering a survey with 3 questions, each with 2

    options. Only one option is correct per question. If John answers randomly, what is the probability that he gets exactly 1 question right?
    A 4/8 Correct Answer Incorrect Answer
    B 3/8 Correct Answer Incorrect Answer
    C 7/8 Correct Answer Incorrect Answer
    D 1/8 Correct Answer Incorrect Answer
    E none of these Correct Answer Incorrect Answer

    Solution

    ATQ, Probability of choosing the right answer = 1/2 Probability of choosing the wrong answer = 1/2 Number of ways to choose 1 correct answer out of 3  = (3/1) = 3 So, the required probability = 3 × (1/2)1 × (1/2)2 = (3×1×1)/(2×2×2) = 3/8 

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