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    Question

    The average marks of all the students increased by 3

    when it was found that marks of one of the students were wrongly taken as 50 instead of 80. Find the total number of students.
    A 8 Correct Answer Incorrect Answer
    B 10 Correct Answer Incorrect Answer
    C 15 Correct Answer Incorrect Answer
    D 12 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−50+80)/N = (S/N) + 3 Or, (S/N) - (S+30)/N = -3 Or, (30/N) = 3 So, 'N' = (30 / 3) = 10 Therefore, total number of students are 10.

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