Multiple choice

The average age of 9 persons is increased by 3 years when one person from amongst them, whose age is 27 is replaced by another person. How old is the new person?

  1. 27

  2. 54

  3. 52

  4. 36

  5. 45
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let the sum of ages be S. The new sum is S - 27 + X = S + (9 * 3). Thus, X - 27 = 27, so X = 54.

AI explanation

When a person is replaced, the new person's age equals the replaced person's age plus the total increase in the sum of ages. The total increase for the 9 persons is 9 times 3 years, which is 27 years. Adding this 27 years to the original person's age of 27 gives 54. The age of the new person is 54.

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