Answer
12:1
Work Step by Step
The odds against E are found by taking the probability that E will not occur
and dividing by the probability that E will occur.
Odds against E = $\frac{P(not E)}{P(E)}$
We find the odds against drawing a 9.
E: {4 cards that are 9's}
P(E) = $\frac{4}{52}$ = $\frac{1}{13}$
P(not E) = 1 - P(E)
= 1 - $\frac{1}{13}$
=$\frac{13-1}{13}$ = $\frac{12}{13}$
Odds against E = $\frac{\frac{12}{13}}{\frac{1}{13}}$ = $\frac{12}{1}$