Statement 1: Say, there are n schools in the city with N1, N2, ..., Nn students in them.sampath wrote:What is the mean age of all students of the city's schools?
1. The average age of the students in each of the city's schools is 12
2. The number of students in each of the city's schools is 70
Therefore, total age of the students of all the schools = (12*N1 + 12*N2 + ... + 12*Nn) = 12*(N1 + N2 + ... + Nn)
Therefore, average age of all students of the city's schools = (Total age of all the students of the city's schools)/(Total number of students of the city's schools) = (12*(N1 + N2 + ... + Nn))/(N1 + N2 + ... + Nn) = 12
Sufficient.
Statement 2: We don't know the number of schools in the city or the total or average age of the students in each school.
Not sufficient
The correct answer is A.
