Not a function.
It's conic section parabola. It's just a relation.
The total number of students is 24 and the total number of boys is 6, therefore
Number of girls = 24 – 6 = 18
Therefore the ratio of the boys to girls is
Number of boys/ number of girls = 6/18 ~ 1/3
The ratio suggests that there is 1 boy for every 3 girls