The average age of 9 students and their teacher is 16 years. The average age of the first four students is 19 years and that of the last five is 10 years. The teacher's age is -

Answer: Option B

According to the question,
Average age of nine students and teacher = 16 years
Then, the total average age of students and teacher = 16 × 10 = 160
And, average age of first 4 students = 19 × 4 = 76
Average age of last 5 students = 10 × 5 = 50
∴ Teacher's age = 160 - 76 - 50 = 34 years