Casino

NOTE: WORK IN PROGRESS, PLEASE DO NOT EDIT YET
A Casino is a term used by Final Fantasy XI players to describe a setup that is run in towns by other players. A casino is essentially what it sounds like, a place for players to choose to 'bet' a certain amount of gil and then perform a /random command to generate a number between 1 and 999. THe result of this 'roll' determines if the players participating wins or loses.

Casino Types
There are two kinds of Casino's in Final Fantasy XI; those run by NPCs, and those run by players.

NPC Run Casino Locations
There are two NPCs in Final Fantasy XI who operate casino's. They are Repat in Norg, and Mileon in Rabao.

NPC Run Casino Mechanics
They way the NPC Casino's work is as follows: - A Player trades the NPC 100gil - The player then automatically rolls a random number between 1 and 6 - The value rolled by the player is then added to a running total - If the current player pushes the running total above 400, then the player wins 10,000gil

Technical Information: ~ When a player wins, the running total is reset to 0 ~ If a player pushes the running total to exactly 400, they win 10,000gil as well as an additional random prize ~ The two Casino NPCs share one running total between them

NPC Run Casinos: Chances of Winning
Your chance of winning off one roll $$p = 1/6 * (6+5+4+3+2+1)/400 = 0.00875$$

So each time you play, you can expect to win the following amount of gil $$E = 10000p - 100(1-p) = -11.625gil$$

In other words, you will lose on average 11.625gil per play. So the house has the advantage. So what are you chances of hitting it big and winning? $$1/p = 114.29 plays$$

So, if you were to play until you won, then (on average) you would be spending 11,400gil and win 10,000gil, resulting in a lose of 1,400gil.

Player Run Casino Locations
Casino's can technically be located in any town; however, they are usually when players tend to congregate normally. The most common places are in Lower Jueno near the Auciton House, and in the Aht Urhgan Whitegate.

Player Run Casino Mechanics
Casino's work in a variety of different ways with different rules absed on the player who is running the casino. The general template used is below.

Roll   Winnings 1-600      Player loses bet 601-900    Player wins 2x their bet 901-999    Player wins 3x their bet

This is just an example. Some casino's are built where if a player rolls a 1 or a 999 they win more. Others will adjust the above numbers to what the casino operator feels comfortable with. In all cases, casino's are designed such that, in the long run, the operator will generate a profit.

Player Run Casinos: Chances of Winning
Chances of winning depend on the odds that the casino operator has setup, as well as the players bet. With the numbers given above, you have the following chances.

You have a 60% chance to lose your bet outright, so... $$X=-(.6 * 100)$$

Then you have a 30% chance to get your original bet back, as well as an additional 1000, so... $$Y=(.299 * 100)$$

Finally, you have a 10% chance to win your original bet, and an additional 2000, so... $$Z=(.099 * 200)$$

$$X + Y + Z = -60 + 29.9 + 9.9 = -20.2$$

So, in the end, on average, for each bet of 1000gil, you will lose 20.2% of whatever you bet each time. In the long run, you will ultimately lose no matter which Casino you play.