Therein lies the problem with your question, the teacher isn't teaching to each individual student seperatly but rather to each individual student independently as a group/class. If he/she met with each student individually then your answer would be correct but the last time I checked, the teacher teaches to each individual student as a group/class, so the correct answer, without any interruptions, would be 360 mins or 6 hrs.(Even if you factor in that some students may need extra attention, there are also those who pick it up on the first lesson so they cancel each other out.)Math lesson: A public school teacher has four 90 minute classes per day and there are 30 students in each class. Assuming no interruptions such as office announcements, pronouncements, assemblies, standardized test, etc., how much time does the teacher have for attention to an individual student?(assume no time lost moving between students and all students getting equal time)?
Answer: 360 minutes/ 120 students= 3 minutes /student/day
What the hell, she cant teach them in 3 minutes. Obviously a bad teacher.
Now you take those 6 hrs a day and multiply by 180 (the number of days in an average school year) and we'll find the teacher has 1,080 hrs to teach any said subject. Now if he/she can't get the job done in 1,080 hrs, regardless of class size, then yes, they are a bad teacher!