Question
The average age of (x + 3) students is 20 years. When
their teacher aged 35 years joins them, the average increases by 1 year. Find x% of 400.Solution
Total age of students = 20(x + 3) years According to question, [20(x + 3) + 35] = (20 + 1)(x + 3 + 1) 20x + 60 + 35 = 21x + 84 20x + 95 = 21x + 84 21x – 20x = 95 – 84 x = 11 So, 11% of 400 = 44
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