Question
The average age of (x + 1) students of a class is 20 years.
If the 50 years old class teacher is also included then average age of the class gets increased by one year. Find x% of 250.Solution
Total age of students = 20(x + 1) years
According to question,
[20(x + 1) + 50] = (20 + 1)(x + 1 + 1)
20x + 20 + 50 = 21x + 42
21x β 20x = 70 β 42
x = 28
So, 28% of 250 = 70
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