The odds for winning a prize are calculated based on the total number of tickets purchased divided by the maximum number of tickets that can be issued.
For example, if a competition has a maximum of 2000 tickets and someone purchases 1 ticket, their chances of winning a prize is 1 in 2000.
Multiple prizes
If a competition has more than 1 prize, then the chances of winning a prize increase.
For example, if a competition has a maximum of 2000 tickets and has 6 prizes, if someone purchases 1 ticket, their chances of winning a prize is 1 in 333.3
The odds displayed on each competition are calculated based on the maximum number of tickets being sold and all tickets having the correct answer to the entry-question attributed to them. If less tickets are sold and/or entrants answer the entry-question incorrectly, the chance of winning increases.