### Author Topic: Question for the math people  (Read 4932 times)

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#### Tollens

##### Question for the math people
« on: December 06, 2013, 11:23:39 PM »
Is it better to bet 4 numbers on one spin or 1 number on 4 spins?

I was told the odds are the same, but given no math to back that claim, I was forced to use logic and concluded that 4 on one spin must be better.

My reasoning was that I would rather have two choices on one flip of a coin (100%) than 1 choice for two flips.

But I have the impression that some sort of bell curve is at work given bets over spin chances when you can not have 100 percent chance of winning.

Anyone have the math on say 38 chips, what is the optimal amount of numbers to bet each spin for best odds of winning?

#### kav

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##### Re: Question for the math people
« Reply #1 on: January 05, 2014, 06:45:47 PM »
Hello Tollens,

Good question.

Roulette is an exceptionally well balanced game and that's one of its many charms.
No method offers an "advantage" in the sense of "being better than the other",  but they do offer different risk-reward parameters. To put it philosophically, you cannot turn the odds in your favor, but you can still use a strategy

Let's take these 3 scenarios:
1) Bet 4 units in 4 different numbers for 1 spin
You have 4/37 (~11%) 27chance of winning 32 units (total 36)  5,4
You risk the loss of 4 units.

2) Bet 4 units on 1 number for 4 spins
Your chance of winning at least 1 bet is 1-(36/37)(36/37)(36/37)(36/37) = ~10,5%
But in this scenario you can win on the first spin, in which case you only risk 1 unit instead of 4. Or you could win multiple times (up to 4 times) if you were extremely lucky. So the chance of win in this scenario is slightly less than the previous, but offers some extra benefits.

3) Bet 4 units on the same number
Your chance of winning is 1/37 =~2,7% , but in case of a win you gain 140 units! (total 144)
You risk the loss of 4 units.

The conclusion is that there are no better or worse bets on European roulette. There are only strategies, and we can decide our bets to fit our strategies....

#### dobbelsteen

##### Re: Question for the math people
« Reply #2 on: January 19, 2014, 09:49:09 PM »
Kav I can agree with you. A player doesnot play a single spin but a session. For every spin the EV is the same.

A similar question is as followed.

Player A bets two units on dozen1 and player B bets two units on dozen 2 and two units on dozen 3.

Who is the smartest

I have posted this question also on an other forum.

#### dobbelsteen

##### Re: Question for the math people
« Reply #3 on: January 24, 2014, 10:45:01 AM »
No one dare to answer who is the smartest player.
In my opinion it is player A. I shall explain.
Both play a system and the probability is they will loss 2.7% of the bets. Assume they play 74 spins. The chances on a profit are for both equal. Player A losses 2.7% of 148 units or 4 units and player B 8 units. However, the chances are equal, player B has a larger risk to loss more money.
In spite of this conclusion, players mostly prefer on odds with a higher expectation

#### kav

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##### Re: Question for the math people
« Reply #4 on: January 24, 2014, 02:38:55 PM »
No one dare to answer who is the smartest player.
In my opinion it is player A. I shall explain.
Both play a system and the probability is they will loss 2.7% of the bets. Assume they play 74 spins. The chances on a profit are for both equal. Player A losses 2.7% of 148 units or 4 units and player B 8 units. However, the chances are equal, player B has a larger risk to loss more money.
In spite of this conclusion, players mostly prefer on odds with a higher expectation

Hi,

I'm not sure I agree completely.  Two points:

1. I think you are overestimating the impact of the casino advantage to the success of our system.
2. The only reason you consider the A player smarter is because he bets less each spin so he loses less according to the expected value (-2,7%) But if this is your main criteria, then the smartest player of all is the one who doesn't bet at all.

Let me reverse your question, so you can see the futility of evaluating strategies based on the house edge:
If both players had a bankroll of 100 units and both bet a total of 100 units, the A playing for 50 spins and the B playing for 25 spins, and then they stop,  who is the "smartest" player?