Stay informed with the
Recent Articles
Best of Alan Krigman

# Will this system work to get the advantage at roulette?

26 August 2013

Question: A friend told me a roulette system based on the third 12-number column of the betting layout having eight red and four black positions. You bet \$5 on this column and \$5 on black, and should win an average of \$25 in every 38 spins. Is this true?

Answer: I've run into this error before. Here's how the system is usually explained for 38 "statistically-correct" spins. Note that columns pay 2-to-1; blacks pay 1-to-1 and either lose half or everything on 0 or 00 depending on the rules at particular casinos.

(a) Zero and double zero are expected twice; in casinos where outside numbers lose only half on these results, you’d be out \$5x2=\$10 on the columns and \$2.50x2=\$5 on the blacks. A \$15 net loss.

(b) Black is expected 18 times. Of these, 14 should be in the first two columns, so blacks win and columns lose, a break-even. Four should be in the third column, winning \$5x4=\$20 on blacks and \$10x4=\$40 on columns. A \$60 net win.

(c) Red is expected 18 times. Of these, 10 should be in columns one and two, losing both bets – \$10x10=\$100. Eight should be in the last column, winning \$10x8=\$80. A \$20 net loss.
According to this logic, you should lose \$15 on 0 and 00, win \$60 on blacks, and lose \$20 on reds – a \$25 overall profit.

The error is in (c). With red in the first two columns, both bets lose – \$10x10=\$100 – as indicated. What about red in the third column? The column bet earns \$10x8=\$80 but the black bet loses \$5x8=\$40, netting \$80-\$40=\$40. So expected loss is \$100-\$40=\$60, not \$20. In all, you should therefore lose \$15 on (a), win \$60 on (b), and lose \$60 on (c) – a \$15 net loss. Separately, columns win \$10x12=\$120 and lose \$5x26=\$130; blacks win \$5x18=\$90 while losing \$5x18=\$90 plus \$2.50x2=\$5 – the same \$15 net loss.

The results are worse if black loses everything instead of half on 0 or 00. You can plug in the numbers to see how it affects the results.