Odds

Let us see how we define Probability in terms of Odds.

Odds in favour = $\frac{Number \hspace{1ex} of \hspace{1ex} favourable \hspace{1ex} cases}{Number \hspace{1ex} of \hspace{1ex} unfavorable \hspace{1ex} cases}$

Odds against = $\frac{Number \hspace{1ex} of \hspace{1ex} unfavourable \hspace{1ex} cases}{Number \hspace{1ex} of \hspace{1ex} favorable \hspace{1ex} cases}$