Multiple choice

The average age of a group of 23 persons increases by 4 months, when a person of 20 years is replaced by a new person. The age of the new person is

  1. 27 years

  2. 28 years

  3. 27 years 8 months

  4. 27 years 6 months

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When the average age increases by 4 months for 23 persons, the total age increases by 23 × 4 = 92 months = 7 years 8 months. Since a 20-year-old person is replaced, the new person must be older than 20 by this amount. Therefore, new person's age = 20 years + 7 years 8 months = 27 years 8 months.

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