In a certain class, percentage of students who increased their average grade during spring term compared to that of the fall term was recorded between 6.9% and 7.1%. What could be the least possible number of students in that class?

Answer 1

well,
1/.069 = 14.4
1/.071 = 14.08
if 1 out of 15 made it, that would 6.67%
if 1 out of 14 made it, that would be 7.14%

So, how do you think you have to adjust things?

Answer 2

so would you round it?

Answer 3

No, you have to consider that if 1 student in 14/15 cannot represent a percentage between .69 and .71, how could 2 students do the job? You have to have an integer number of students.
2/18 = 1/14 = 7.14%
2/29 = 6.89%
Still out of bounds

What about 3 students?
3/42 = 1/14 = 7.14%
3/43 = 6.97%
3/44 = 6.81%
So, it looks like 43 is the minimum number of students.