Question
The ages of the students in 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 in the class is 168 years. Find the numbers of students in the class.
Solution
Let the number of students in the class be n.
Let a be the age of youngest student
∴ a = 8 years
Since the age of the students form an A.P. with common difference 4 months or years.
∴ years
Since the sum of the ages of all the students in the class is 168 years.
∴
n = 16
∵ Number of students cannot be negative. Hence, number of students in the class is 16.