ANSWER
4 : 9
EXPLANATION
The total number of people present is the number of females plus the number of males:
[tex]125+100=225[/tex]
The ratio of number of males to total number of people is:
[tex]\frac{100}{225}[/tex]
We have to simplify this fraction. Both 100 and 225 are divisible by 5:
[tex]\begin{gathered} 100\colon5=20 \\ 225\colon5=45 \end{gathered}[/tex]
Therefore:
[tex]\frac{100}{225}=\frac{20}{45}[/tex]
And then again, 20 and 45 are divisible by 5:
[tex]\begin{gathered} 20\colon5=4 \\ 45\colon5=9 \end{gathered}[/tex]
Therefore:
[tex]\frac{100}{225}=\frac{20}{45}=\frac{4}{9}[/tex]
We can't simplify more than that, so the ratio is 4 : 9
