We can write the ratio of a to b like this:
[tex]a\text{ to b}\equiv a\colon b\equiv\frac{a}{b}[/tex]then, if there were 8 children and 20 adults, the ratio of adults to children is:
[tex]\begin{gathered} \text{adults to children:} \\ 20\colon8\equiv\frac{20}{8}=\frac{5}{2}\equiv5\colon2 \end{gathered}[/tex]therefore, the ratio of adults to children is 5:2
