Question
There were 24 students in the class. One of them, who was 18 years old left the class and his place was filled up by a newcomer. If the average of the class was thereby lowered by 1 month, the age of the newcomer is
Solution
Let the average age of 24 men be x β Sum of age of 24 men = 24x If a man replaced, then average age of 24 men = (x β 1/12) β If a man replaced, then sum of age of 24 men = 24 (x β 1/12) = 24x β 2 Let weight of new man be y According to the question 24x β 18 + y = 24x β 2 β y = 24x β 2 β 24x + 18 β y = 16 β΄ Age of new comer is 16 years.
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