Solution
First, we are given the probability of unlocking the treasure chest
[tex]p=\frac{9}{20}[/tex]
To find the odd, we
[tex]\begin{gathered} Favourable\text{ Event = 9} \\ \\ Unfavorable\text{ Event = }20-9 \\ \\ Unfavorable\text{ Event =}11 \end{gathered}[/tex]
So the answer is
[tex]Odd=\frac{9}{11}[/tex]
