X-Files said:
What % is roulette playing black/red, odd/even, etc?
Shouldn't gamble without elementary knowledge of statistics & probability.
Regular double-zero roulette has 38 spots, and each of the those bets (black/red, odd/even) will cover 18 of those spots.
18/38 (probability) x 2 (2-1 payout) = 94.73% expected payback
100 - 94.73 = 5.26% expected house edge
Single-zero roulette has 37 spots, so:
18/37 (probability) x 2 (2-1 payout) = 97.30% expected payback
100 - 97.30 = 2.70% expected house edge
Want to let it ride on a color?
Odds of winning back-to-back (double-zero roulette):
[ 1/(18/38)^N]
1 win = 1 in 2.11 / pays 2-1
2 wins = 1 in 4.46 / pays 4-1
3 wins = 1 in 9.41 / pays 8-1
4 wins = 1 in 19.86 / pays 16-1
5 wins = 1 in 41.93 / pays 32-1
6 wins = 1 in 88.53 / pays 64-1
7 wins = 1 in 186.89 / pays 128-1
8 wins = 1 in 394.5 / pays 256-1
(single-zero)
1 win = 1 in 2.06 / pays 2-1
2 wins = 1 in 4.23 / pays 4-1
3 wins = 1 in 8.68 / pays 8-1
4 wins = 1 in 17.85 / pays 16-1
5 wins = 1 in 36.70 / pays 32-1
6 wins = 1 in 75.44 / pays 64-1
7 wins = 1 in 155.06 / pays 128-1
8 wins = 1 in 318.74 / pays 256-1