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college kid 12-07-2005 06:11 AM

How many spins?
 
How many minimum spins on roulette would it take for there to be a 1% or less of a specific number not hitting at all during that set of spins?

I'm asking for a very specific reason and it's not because I plan on playing roulette!!!

12-07-2005 08:16 AM

Re: How many spins?
 
How many numbers are there on a roulette wheel? I think it's 32 plus the zeros.

So, on a double 0 wheel, the odds of your number not hitting is 33/34. The odds of it not hitting in n spins is (33/34)^n. (33/34)^n = .01 when n = ln(.01)/ln(33/34) = 154.26. So, after 155 spins.

On a single zero wheel, the answer is 150.

WhiteWolf 12-07-2005 02:53 PM

Re: How many spins?
 
Correct logic, but the numbers are wrong - a roulette wheel has 36 numbers. Using this, it is 173 (n=172.68) spins for a double zero wheel and 169 (n=168.08) for a single zero wheel.


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