This is a great example of how to poorly phrase a question so as to be ambiguous.
The answer you are probably supposed to give is "a population". To elucidate: the salary of each teacher in a school includes all the teachers in the school, hence the entire population of teachers in the school.
Another interpretation is that the population is all teachers in all schools, in which case the salary of each teacher in <u>a</u> school is "a sample" of all teachers.
you start by taking 2673 and then you have to divide that 486 and when you do that you get 5.5. Since that question states that each club sold each item for the same price then each item was sold for five dollars and fifty cents.