Let number of boys be 300.
Number of girls = 200
Boys holding scholarship = (20/100) x 300 = 60
Girls holding scholarship = (25/100) x 200 = 50
Total student holding scholarship = 60 + 50 = 110
∴ Percentage of students not holding scholarship = [(500 -110) / 500] x 100%
= (390/500) x 100 %
= 78%