Question

You place a bet on the number 21 in roulette. The probability of winning is 1 38 , and the company hosting the casino night for a city fundraiser gives the payoff odds as 35:1. What are the odds that the ball will land on the number 21?



1:37


1:38


1:35


1:21

Answer 1

The probability of winning is 1 38
so the odds are one in thirty-eight

Answer 2

1:38 ???

Answer 3

thanks

Answer 4

I disagree,
Odds and probability are defined slightly different.

The odds of some event happening
= prob( event) : prob(not the event)

so if prob(a 21 ) = 1/38
then the prob(not a 21 ) = 1 - 1/38 = 37/38

odds in favour of a 21 = (1/38) / (37/38)
= (1/38)(38/37)
= 1 : 37