Multiple choice

The average age of 23 students and class teacher is 16 years. If the class teacher's age is excluded, the average reduces by one year. What is the age of the class teacher?

  1. 39 years

  2. 42 years

  3. 41 years

  4. 38 years
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A Correct answer
Explanation

Let total age of 23 students + teacher = 24 × 16 = 384 years. Average of 23 students alone = 15 years (reduces by 1), so their total = 23 × 15 = 345 years. Teacher's age = 384 - 345 = 39 years. This is a standard average problem where removing one value changes the average.

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