The average age of a group of 35 students is 15 years. If a teacher is included in the group, then the average age increases by 2 months. The age of the teacher (in years) is
Answer & explanation
Correct answer: option 3
Average age of 35 students only = 15 years
Average age of 35 students + 1 class teacher = 15 years 2 months
We know that,
Average = (Total sum)/(Total numbers)
Total age of 35 students only = 35 × 15 = 525
Total age of 35 students and the class teacher = 36 × 15.16 = 546
Age of teacher = 546 - 525 = 21 years