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    Question

    The average marks of all the students decreased by 2

    when it was found that marks of one of the student were wrongly interpreted as 80 instead of 40. Find the total number of students.
    A 10 Correct Answer Incorrect Answer
    B 20 Correct Answer Incorrect Answer
    C 25 Correct Answer Incorrect Answer
    D 15 Correct Answer Incorrect Answer

    Solution

    Let number of students be 'N' and sum of marks of all the students be 'S'. ATQ: We have, [(S - 80 + 40) /N] = (S/N) - 2 Or, (S/N) - [(S - 40) /N] = 2 Or, (40/N) = 2 So, 'N' = (40/2) = 20 Therefore, total number of students are 20.

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