If A = {Student in VIII class of age 13 years} and B = {Students in IX class of age 13years}, then `A nn B = "____"`. (`phi` students of age 13 years)

The average age of 30 students in a class is 15 years. If 6 students of this class have the average age of 16 years, then the average age of the remaining 24 students would be (a) 14 years (b) 14 years 3 months (c) 14 years 6 months (d) 14 years 9 months

If the average age of 40 students in class I is 10 yr and the average age of 30 students in class II is 12 yr, then find the average age (in years) for all students. (A) 11 (B) 10.54 (C) 10.58 (D) 10.85

There are 30 students in a class .The average age of the first 10 students is 12.5 years .The average age of the remaining 20 students is 13.1 years .What is the average age (in years ) of the students of the whole class ?

In a class of 10 students the average age was 16 years. When two students left the class, the average age of the remaining students became 16.25 years. What is the total age of the students left

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.

The ages of the students of a class form an A.P. whose common difference is 4 months. If the youngest student is 8 years old and the sum of the ages of all the students of the class is 168 years, find the number of students in the class.