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.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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