单选题 King School has an enrollment of 900 students. The school day consists of 6 class periods during which each class is taught by one teacher. There are 30 students per class. Each teacher teaches a class during 5 of the 6 class periods and has one class period free. No students have a free class period. How many teachers does the school have?

A、 25
B、 30
C、 36
D、 60
E、 150

【正确答案】 C

【答案解析】If each teacher has 5 class periods a day and each class has 30 students, then each teacher has (5)(30) students per day. Each of the 900 students has 6 classes per day, from which it follows that all the teachers combined have a total of (6)(900) students per day. Therefore, the school has