Multiple choice

The average age of 27 girls and the teacher is 14 years. When the teacher's age is excluded, the average age decreases by 1. What is the age (in year) of teacher?

  1. 41

  2. 42

  3. 39

  4. 40
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Total age of 28 people (27 girls + teacher) = 28 × 14 = 392 years. When teacher excluded, 27 girls have average 13 years, so their total = 27 × 13 = 351 years. Teacher's age = 392 - 351 = 41 years. Option B (42) is off by 1 year.

Keep practicing — related questions