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Paco
Lv 7
Paco asked in Science & MathematicsMathematics · 8 years ago

math craps endurance question?

For people familiar with craps (dice game), the average number of rolls a dice before people "7-out" in craps is just over 8. What are the odds of passing 30 rolls? 50 rolls? or 100 rolls?

2 Answers

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  • ?
    Lv 6
    8 years ago
    Favorite Answer

    The probability of 7 on a roll is 1/6. So the probability of a non-7 is 5/6. The probability of N non-7's is (5/6)^N.

    But that is not the answer. I think you need to consider the probability of rolling your point before N rolls, as well, and that reduces the probability substantially.

    You get into the probability your point is m, and given that, what is the probability you will make your point before N rolls, and combine all this together until your head hurts.

    I give up. It is a very good question and I bet there is is a simple answer.

  • Anonymous
    6 years ago

    this is about the length of a craps shooter;s hand

    the math is easy when one sees how it is done in Excel for example.

    the answers for:

    to make the 31st roll: 1 in 69.86

    to make the 51st roll: 1 in 1,346.67

    to make the 101st roll: 1 in 2,197,679.31

    there is more in the other question here:

    https://answers.yahoo.com/question/index?qid=20130...

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