Answer:
A = 12
B = 18
C = 14
that's your solution.
number of sections is A + B + C which becomes 12 + 18 + 14 which is equal to 44
number of students in each course is 100A + 50B + 200C = 1200 + 900 + 2800 which is equal to 4900
number of teachers in each course is A + B + 2C which becomes 12 + 18 + 28 which is equal to 58.
12 sections in ancient history have 1200 students and 12 teachers.
that's 1 teacher per course and 100 students per section.
18 sections in medieval history have 900 students and 18 teachers.
that's 1 teacher per course and 50 students per section.
14 sections in modern history have 2800 students and 28 teachers.
that's 2 teachers per course and 200 students per section.
answer to your questions is:
12 sections of ancient history and 18 sections of medieval history and 14 sections of modern history.