Answer
1:2
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 are asked to find the odds against rolling a number less than 5.
S: {1,2,3,4,5,6}
E: {1,2,3,4}
P(E)= $\frac{4}{6}$ = $\frac{2}{3}$
P(not E) = 1 - P(E)
= 1 - $\frac{2}{3}$
=$\frac{3-2}{3}$
= $\frac{1}{3}$
Odds against E = $\frac{\frac{1}{3}}{\frac{2}{3}}$ = $\frac{1}{2}$
