Phone interview with standard questions including how many students have you had on average. Be careful with this question or ask if it they require an answer.
Next was an in-person interview. Again standard questions. However, upon questioning their reasoning for not hiring me after the fact, they explicitly said that it was because they need teachers coming in to have an average of 25 students. This should be noted on the requirements if that alone can truly be an explanation ( they didn't offer any others so that is all I have to go on).