What is the average number of students for schools with a pupil to teacher ratio of 25.1?
CREATE TABLE "schools" (
  "school_name" text,
  "city" text,
  "students" real,
  "fte_teachers" real,
  "pupil_teacher_ratio" real
);
SELECT AVG("students") FROM "schools" WHERE "pupil_teacher_ratio"=25.1;