Odds correlate to probability e.g a 3/1 bet is expected to win one in every 4 attempts. Hence the probability is 25%.

Odds of 1/3 will pay only 33.33 percent of the amount risked, so a bet ofR$100 would profitR$33.33 if it should win. Odds of 1/1 will pay the same amount risked, so a bet ofR$100 would profitR$100 if it should win.