Question

The mean number of students in a classroom at school a is 32.5 and there are 25 classrooms. The mean number of students at school b is 29.6 in 12 classrooms. At school c the mean in each class is 15.3 for 10 classrooms. What is the mean number of students per classroom for all the schools combined?

Answer 1

We have given three school there, School A, School B and School C.

We are going to use following formula.

Total number of student in a school = Mean of number of student × Number of classrooms.

School A

Mean of students in School A = 32.5.

Number of classroom in School A = 25.

Number of students in School A = Mean × number of classrooms = 32.5×25 = 812.5

School B

Mean of students in School B = 29.6.

Number of classroom in School B = 12.

Number of students in School B = Mean × number of classrooms = 29.6×12 = 355.2

School C

Mean of students in School C = 15.3.

Number of classroom in School C = 10.

Number of students in School C = Mean × number of classrooms = 15.3×10 = 153.

Total sum of number of classes in all schools = 25+12+10 = 47.

Total sum of all students in all schools = 812.5 +355.2 +153 = 1320.7 .

The mean number of students per classroom for all the schools combined =

$\frac{Total \ sum \ of \ all \ students \ in \ all \ schools}{Total \ sum \ of \ number \ of \ classes \ in \ all \ schools}$

= $\frac{1320.7}{47}$ = 28.1

The mean number of students per classroom for all the schools combined= 28.1