The smallest possible number of students in a class if the girls in the class are less than 50% but more than 48% is

Odd n=2g+1: g/(2g+1)>0.48 needs g>12, so g=13, n=27 (13/27=0.481). Even n needs g<=n/2-1 with (n/2-1)/n>0.48, i.e. n>50. 25 gives exactly 48% (not more). Smallest is 27.