Suppose 38 players each bet one chip on each different number. One person will win 35 chips and the rest will lose. So in effect the casino makes a profit of 3 chips out of 38 chips.

3/38 = x/100

38x = 300

This is around 7.89%.

Note: if the player wins 35 chips plus gets his own chip back, this would be 2 chips out of 38 wagered, adjust answer accordingly.

The house advantage on all types of roulette bets is 1/19 or 5.26%. So, this is the casinos profit. I’ll find you a table, but if you ever go to a Vegas casino or watch the Discovery channel, they will tell you this. Roulette is one of the games in which the house holds a large advantage. Blackjack is your best bet. I’m pretty sure the house advantage is around 1%. Let me find a table quick:

The previous poster is correct about blackjack offering only about a 1% house advantage. In practice, however, the house does much better than that due to incorrect plays by the players – in other words, the casino gets most of its profit off player mistakes. In blackjack, you have to know what you’re doing to keep the house advantage at 1%.

I don’t know how to play the Roulette but from what you have stated about the odds on single number bet, 35:1 means that there are 35 bets against it and 1 bet for it. So the Casino expects to score 35/36 times and loose only 1/36 times. So for each dollar bet or token whic might cost say $1 the casino makes 1×35/36 and loose 1×1/36. That is the expected casino gain is (1×35/36 -1×1/36) that is the casino hopes to win 97.2% of the time.
If there are 38 players casino will win $37 out of which it will pay back $37 as odds in 35 to 1 and for 1 it will pay $35 total pay offs as $62 to collection of 38 a loss of $24. To avoid this the token value might be more than$1. If we know the token or chip value then we can calculate the house advantage otherwise not.