Students Arrive at a University Business Library During Peak Evening

Multiple Choice

Students arrive at a university business library during peak evening hours at a rate of 40 students every half hour. Each student stays an average of two hours. On average, how many students are in the library at any one time?

A) greater than 120 students
B) greater than 80 but less than or equal to 120 students
C) greater than 40 but less than or equal to 80 students
D) less than or equal to 40 students