Multiple choice

The average age of $29$ boys of a class is equal to $14$ years. When the age of the class teacher is included the average becomes $15$ years. Find the age of the class teacher.

  1. $44\ years$
  2. $40\ years$
  3. $52\ years$
  4. $66\ years$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sum of ages of 29 boys = 29 * 14 = 406. Sum of ages with teacher = 30 * 15 = 450. Teacher's age = 450 - 406 = 44 years.

AI explanation

The total age of the 29 boys is their average multiplied by the number of boys, so 29 times 14 gives a total of 406 years. When the teacher is included, the total age for 30 people becomes 30 times 15, which equals 450 years. The age of the class teacher is the difference between the new total and the old total, giving 450 minus 406 equals 44 years.

Keep practicing — related questions