The first step to solve this problem, you have to compute first for the total number of students:
6 math classes x 27 students per class = 162 students
Now, you know that there are 162 students all in all in the school. The next step is to compute for the total cost of both the book and the calculator per student.
$45.10 (Book) + $57.80 (Calculator) = $102.90 (total cost per student)
To compute for the total cost that the school will pay, you have to multiply the total cost per student to the number of students in school.
$102.90 per student x 162 students = $16,669.80
Therefore, the total cost the school will pay is $16,669.80.