Answer
497:3
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 that a person who purchased 30 of 5000 raffle tickets will win a trip.
P(E) = $\frac{30}{5000}$ = $\frac{3}{500}$
P(not E)= 1- P(E)
=1 - $\frac{3}{500}$
=$\frac{500 - 3}{500}$
=$\frac{497}{500}$
Odds against E = $\frac{\frac{497}{500}}{\frac{3}{500}}$ = $\frac{497}{3}$
