The ratio of the number of boys and girls in a school is 3 : 2. If 20% of the boys and 25% of the girls are scholarship holders, what percentage of the students do NOT get scholarship?

Lets assume , no of boys are 3x and no. of girls are 2x.

Now , no of boys who are  holders are 20 percent of 3x i.e. $$\frac{20}{100}$$x 3x i.e 0.6x

Now , no of girls who are scholarship holders are 25 percent of 2x i.e $$\frac{25}{100}$$x 2x i.e 0.5x

Therefore total scholarship holders are 0.6x + 0.5x i.e. 1.1x

Total students = 3x + 2x = 5x

Therefore students who don't get scholarships 5x - 1.1x = 3.9x

Therefore Percentage of students who have no scholarships= $$\frac{3.9x}{5x}*100$$= 78 percentage