Multiple choice

The mean age of a group of 10 friends is 27 years. After 3 years, the mean of the same group will be

  1. 28

  2. 29

  3. 30

  4. Not enough information available
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C Correct answer
Explanation

If the mean of 10 people is 27, the sum of their ages is 270. After 3 years, each person ages by 3 years, so the total sum increases by 10 * 3 = 30. New sum = 300. New mean = 300 / 10 = 30.

AI explanation

The total sum of the current ages of the 10 friends is 10 multiplied by 27, which equals 270 years. After 3 years, each of the 10 friends will be 3 years older, meaning the total age increases by 10 multiplied by 3, adding 30 years to the sum. The new total age becomes 300, and dividing this by the 10 friends gives a new mean age of 30 years.

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