Question
The average age of a group of students in a school is 14 years. If 20% of them have an average age of 12 years and 40% have an average age of 16 years, then the rest students have an average age of
Solution
Let the total number of students be 100 So sum of the age of total students = 100 x 14 = 1400 20% of the students have average of 12 = 20% of 100 x 12 = 240 40% of the students have average of 16 = 40% of 100 x 16 = 640 Average of rest of the students = 100% - 60% = 40% Required average = (1400 – 240 – 640)/40 = 13 years Alternate method:
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