how do you show the work for this?

Question

School A has 216 students with 12 classrooms. School B has 104 students with 4 classrooms. How many students need to transfer from school B to school A so that they each have the same number of students in each classroom?

Answer 1

The total number of students is the sum of each.

The average would be that sum divided by the total # of classrooms. 

You would transfer the students above that average.

 

school A has 216 students / 12 classrooms or 18 Students per classroom

school B has 104 students / 4 classrooms or 26 students per classroom

the average would be(216 + 104) / (12 + 4) or 320/16 = 20 students per classroom

 

Since school B has more than the average you would transfer (26 - 20) students per 4 classrooms or 24 students

Answer 2

Currently School A has 216/12 = 18 students/room
              School B has 104/4 = 26 students/room
 
Since school A has the most rooms with 12 let's check with
transferring multiples of 12 students from school B to School A:
 
If we transfer 12 students:
A has 228/12 = 19 students/room
B has 92/4 = 23 students/room
 
If we transfer 24 students:
School A:  240/12 = 20 students/room
School B:  80/4 = 20 students/room