Question: odds 3 1 what does this mean?
Answer: "3:1" or "3 to 1" means that the payoff is 3/1 (or "three times") the original bet, if it succeeds. Such a payoff reflects the bookmaker's (or counterparty's) belief that the odds of success are less than 1 in 4 (4=1+3) or less than 25%.