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Re: It is not unusual to see the ball fall into a black slot on a roulette [#permalink]
Bunuel wrote:
It is not unusual to see the ball fall into a black slot on a roulette wheel four times in a row. But for it to fall five or six times in a row into the same color is very unusual. Therefore you can win money by waiting for a run of five of the same color and then betting against that color.

If the roulette wheel in question is a fair wheel, which of the following observations or facts, if it were true, would best reveal a fallacy in the logic?


A. If there were a reliable way to win at roulette it would be well-known by now.

B. It is hard for a player to keep track of what went before for the time required.

C. The probability of getting a particular color decreases with the number of times the color has appeared.

D. The probability of getting a particular color is always the same no matter what has gone before.

E. A person who makes money this way once or twice, will carry on to lose that money after a few more times.


IMO D
If the probability of getting a color is always same then we can't predict anything.
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Re: It is not unusual to see the ball fall into a black slot on a roulette [#permalink]
IMO D as probability of any event is independent of the previous events ....considering events in the play are independent
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Re: It is not unusual to see the ball fall into a black slot on a roulette [#permalink]
It is hard for a player to keep track of what went before for the time required.

Ans should be B according to me because if a player cannot keep track of which bets he went for, then argument will fall apart.

I can be wrong here. Let me know what you think
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It is not unusual to see the ball fall into a black slot on a roulette [#permalink]
The question asks about the fair chances. Only D presents the flaw in the reasoning as it brings out this 'fair' aspect.

Answer should be D.
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Re: It is not unusual to see the ball fall into a black slot on a roulette [#permalink]
A. If there were a reliable way to win at roulette it would be well-known by now.
- irrelevant. It is not a fallacy.

B. It is hard for a player to keep track of what went before for the time required.
- irrelevant.

C. The probability of getting a particular color decreases with the number of times the color has appeared.
- it kind of strengthens the argument. It does not represent a fallacy in the logic.

D. The probability of getting a particular color is always the same no matter what has gone before.
- yes. This is something which I presupposed. This tells us that probability is always the same, so we cannot say when it will happen and when not. Keep.

E. A person who makes money this way once or twice, will carry on to lose that money after a few more times. - irrelevant.

Thus, D wins.

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Re: It is not unusual to see the ball fall into a black slot on a roulette [#permalink]
Half a chance is no any better deal for either of the parties involved.

Hence D.
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Re: It is not unusual to see the ball fall into a black slot on a roulette [#permalink]
Merged posts.Please search before posting.

Thanks!
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Re: It is not unusual to see the ball fall into a black slot on a roulette [#permalink]
Expert Reply
The ball has fallen on black 5 times in row, so of course it’s gonna fall on black the next time!

The ball has fallen on black 5 times in a row, so of course the time has come for it to fall on red!

Uhhh...

Posted from my mobile device
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Re: It is not unusual to see the ball fall into a black slot on a roulette [#permalink]
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