When you set up ratios and proportions like this, first write down in words how your setting up the ratios.
Are you doing [tex]\dfrac{~~\text{number of students~~}}{\text{number of teachers}}[/tex] or [tex]\dfrac{\text{number of teachers}}{~~\text{number of students~~}}[/tex].
Once you do that, just stay consistent in the equation you set up.
(Did Elisa stay consistent?)
