Help with Probability of a Modified Roulette game

grahamH17

New member
Joined
Jan 21, 2016
Messages
1
Hey all. Wondering if you can help me out with the chances of winning in a round of N spins in a modified game of roulette

THE GAME

15 numbers, red/black and green

0 : GREEN
1-7 : RED
8-14 : BLACK

Chances of getting red/black = (7/15)
Chances of getting green = (1/15)

THE STATEGY

To bet one color (red/black) until you get that color, then switch to the other color

The first thing I want to calculate is the chance of getting to spin N and winning on spin N. Say for this example N = {1,2,3}.
I hope this makes sense, but I think that the chance of getting to and winning on spin N should be (the chance of getting to spin N) * (the chance of winning on spin N)

The chance of getting to spin N = (8/15)^(n-1)
The chance of winning on spin N once you are on spin N = (7/15)
So the chance of getting to and winning on spin N = (8/15)^(n-1)*(7/15)

S1 = The chance of winning on the first spin = 1*(7/15) = 0.46666667
S2 = The chance of winning on the second spin = (8/15)*(7/15) = 0.248888888
S3 = The chance of winning on the third spin = (8/15)^2*(7/15) = 0.132740741

Please correct me if this is wrong

So the next thing I'm trying to figure out is the chance of you winning in a round of N spins. So for this example N = 3. This is where I am unsure how to calculate your chance of winning. Do you simply just add up the chances?

So your chance of winning in 3 spins would simple be S1 + S2 + S3 = 0.848296291 = 84.83%

Does this all make sense?

Thanks in advance
 
Hey all. Wondering if you can help me out with the chances of winning in a round of N spins in a modified game of roulette
THE GAME
15 numbers, red/black and green
0 : GREEN
1-7 : RED
8-14 : BLACK
I really hate to disappoint you, but it makes absolutely no difference how one bets as long as one does bet on green.
If it is a fair wheel, it makes no difference how the colours are distributed or which of red or black you bet on the probability of winning is \(\displaystyle \dfrac{7}{15}\). That means that the HOUSE has a slight advantage.
 
Hey all. Wondering if you can help me out with the chances of winning in a round of N spins in a modified game of roulette

THE GAME

15 numbers, red/black and green

0 : GREEN
1-7 : RED
8-14 : BLACK

Chances of getting red/black = (7/15)
Chances of getting green = (1/15)

THE STATEGY

To bet one color (red/black) until you get that color, then switch to the other color

The first thing I want to calculate is the chance of getting to spin N and winning on spin N. Say for this example N = {1,2,3}.
I hope this makes sense, but I think that the chance of getting to and winning on spin N should be (the chance of getting to spin N) * (the chance of winning on spin N)

The chance of getting to spin N = (8/15)^(n-1)
The chance of winning on spin N once you are on spin N = (7/15)
So the chance of getting to and winning on spin N = (8/15)^(n-1)*(7/15)

S1 = The chance of winning on the first spin = 1*(7/15) = 0.46666667
S2 = The chance of winning on the second spin = (8/15)*(7/15) = 0.248888888
S3 = The chance of winning on the third spin = (8/15)^2*(7/15) = 0.132740741

Please correct me if this is wrong

So the next thing I'm trying to figure out is the chance of you winning in a round of N spins. So for this example N = 3. This is where I am unsure how to calculate your chance of winning. Do you simply just add up the chances?

So your chance of winning in 3 spins would simple be S1 + S2 + S3 = 0.848296291 = 84.83%

Does this all make sense?

Thanks in advance
Yes, you could simply just add up the chances. However, there is an easier way. Since the chance of winning or loosing in n spins is 1, the chances of winning is just 1 minus the chances of losing which is 1-(8/15)n. However, be careful with that. Suppose you were to 'double down' with an initial $10 bet and lost 5 times in a row. The sixth bet would be a $320 bet and, if you won, your total winnings would be $10.
 
Top