Answer:
6 more teachers are required.
Explanation:
Total number of students = 616
No of teachers = 616/28= 22
Increase in students = 18%
= 18/100*616= 110.88= 111
Total number of students = 616+111= 727
Decrease in teachers = 9%
= 9/100*22= 1.98= 2
New number of teachers= 20
Now Average is 28 students per teacher so
727/28= 25.96= 26 teachers are required for the total number of 727 students. The school has already 20 teachers so they need 6 more teachers.