assuming a direct proportional variation.
[tex]\bf \begin{array}{ccll}
students&teachers\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
500&30\\
750&t
\end{array}\implies \cfrac{500}{750}=\cfrac{30}{t}\implies t=\cfrac{750\cdot 30}{500}\implies t=45[/tex]
