The ratio is,
[tex]b\colon g=2\colon3[/tex]This means that , the boys and the girls constitute a fraction of
[tex]\begin{gathered} b=\frac{2}{5} \\ g=\frac{3}{5} \end{gathered}[/tex]of the total number. The total number of students is 125. Therefore, we have,
[tex]\begin{gathered} b=\frac{2}{5}\times125=50 \\ g=\frac{3}{5}\times125=75 \end{gathered}[/tex]Thus, there are 50 boys and 75 girls.