The event of rolling a fair die and getting 2 or 4 or 5 or 3 has 4 possible outcomes. Either one can get 2 or 4 or 5 or 3
Number of possible ways of getting favorable outcome =4
Now remaining outcomes which are not included into event are getting 1 or 6. There are 2 outcomes.
Number of possible ways of getting unfavorable outcome =2
Odds for the event = Number of ways getting favorable outcome / Number of ways getting unfavorable outcome
Odds for given event = 4 /2 = 2/1
Odds against eventSo the odds for event of rolling a fair die and getting 2 or 4 or 5 or 3 is 2:1
Odds against event = Number of ways of getting unfavorable event / Number of ways of getting favorable event
= 2/4
=1/2
So the odds against event of rolling a fair die and getting 2 or 4 or 5 or 3 is 1:2