30 student average age is 20. If teacher entered in the class then the average increased one more then find the age of teacher.

The average age of a class of 39 students is 15 years.If the age of the teacher be included, then the average increases by 3 months.Find the age of the teacher.

The average age of 27 students of a class is 22. If the age of the teacher is also added to their ages, then the average increases by one. Find the age of the teacher

Average age of 17 student of a class is 16 years. If a new student join the class then average age becomes 20. Then find the age of new student.

In a class, the number of boys and girls are distinct. The average age of all the student in the class equals the average of the average age of the boys and the average age of the girls. The sum of the average age of the boys and the average age of the girls is 10 years. Find the average age (in years) of the boys of the class

There are 25 teacher in a school , the average age of teacher is 40. If a teacher of 60 years of age is retired than a new teacher is appointed in place of him and the average decreases to 39 . find the age of teacher appointed