there are 550 students how many teachers were there be in ratio form

The ratio of teacher to student is equivalent so teacher to the student ratio is same for all the school A, B, C and D.
Equate the teacher to school ratio for school A and school C to obtain the number of teachers in school C.
[tex]\begin{gathered} \frac{15}{330}=\frac{x}{550} \\ x=\frac{15\cdot550}{330} \\ =25 \end{gathered}[/tex]The number of teacher is school C is 25.
Equate the teachers to students ratio for the school A and school D to obtain the number of students in school D.
[tex]\begin{gathered} \frac{15}{330}=\frac{36}{y} \\ y=\frac{36\cdot330}{15} \\ =792 \end{gathered}[/tex]
The number of students in school D is 792.