We have that the odds in favor are 2 : 9, we can also write it like this:
[tex]2\colon9=\frac{2}{9}[/tex]now, the odds agains the event is the complement of the odds in favor, then:
[tex]1-\frac{2}{9}=\frac{7}{9}[/tex]therefore, the odds against the event are 7:9
