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Thu 15 Dec, 2005 04:10 am
This weekend I and a few friends were playing with 5 dice.
a: At some moment my friend throws five fives in one throw.
What are the odds of this?
b: Then it's my turn I threw five fives in two throws.
What are the odds of this?
c: Then it my second friend turn and she also throws five
fives in two throws.
Finally: what are the odds of abc happening in a row?
I'll give probability. Odds are p/(1-p).
a) 1/6^5
b) 1/6^10 (if five fives were thrown twice in a row)
[(6^5)-1]/6^10 (if five fives were not thrown on the first roll, but were thrown on the second roll)
c) same as (b)
Finally) a*b*c
Impossible to know unless you specify how the dice are marked.
From the description, it sounds like the dice are marked "five" on all faces, so the odds are 1:1.
I assumed standard dice.
However, I wonder if I understood (b). Do you mean there were a total of five fives between the two rolls, both rolls consisted of five fives, or the first roll was not five fives, but the second roll was?
I didn't cover the first case.
This thread belongs in the math & science forum, not here. (That's my way of saying, I believe markr is right, but I ain't no expert mathe...mothem...mathing... uh... I don't do good with numbers.)
If (b) means a total of five fives in two rolls, then the probability is:
C(10,5)*5^5/6^10 = 252*5^5/6^10
which is about 13/1000
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