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1. Two fair six sided dies are rolled.
Both dies are rolled 20 times.
Find p that at least once the two dice will show 6?
2. (Original post by English-help)
Two fair six sided dies are rolled.
Both dies are rolled 20 times.
Find p that at least once the two dice will show 6?
The probability of rolling two sixes when two dice are rolled is 1/6 x 1/6 = 1/36

The dice are rolled twenty times. Let X be the number of times a pair of sixes is rolled. Then X ~ B(20, 1/36)

Does this help? If any of this doesn't make sense to you, please tell us if you are doing GCSE/A Level and what topics you have done.
3. (Original post by Notnek)
The probability of rolling two sixes when two dice are rolled is 1/6 x 1/6 = 1/36

The dice are rolled twenty times. Let X be the number of times a pair of sixes is rolled. Then X ~ B(20, 1/36)

Does this help? If any of this doesn't make sense to you, please tell us if you are doing GCSE/A Level and what topics you have done.
The first bit makes sense to me as the probability of getting a 6 is 1/6 on a fair die

Okay so its binomial, it makes sense , its how I apply it into a formula which confuses me , I have just started A level maths
4. (Original post by English-help)
The first bit makes sense to me as the probability of getting a 6 is 1/6 on a fair die

Okay so its binomial, it makes sense , its how I apply it into a formula which confuses me , I have just started A level maths
X ~ B(20, 1/36) and you need to find P(X ≥ 1). And P(X ≥ 1) = 1 - P(X = 0).

Do you know how to carry on from here? If not, you may need to check your textbook, watch a video or ask your teacher.
5. (Original post by Notnek)
X ~ B(20, 1/36) and you need to find P(X > 1). And P(X > 1) = 1 - P(X = 0).

Do you know how to carry on from here? If not, you may need to check your textbook, watch a video or ask your teacher.
Okay so I'll try doing it now , thanks
6. (Original post by Notnek)
X ~ B(20, 1/36) and you need to find P(X > 1). And P(X > 1) = 1 - P(X = 0).

Do you know how to carry on from here? If not, you may need to check your textbook, watch a video or ask your teacher.
Can you confirm to me that P(X=0)= 0.56926 , well thats what I got on my calculator but it seems wrong
7. (Original post by English-help)
Can you confirm to me that P(X=0)= 0.56926 , well thats what I got on my calculator but it seems wrong
That's what I got

If you think about it, 1/36 is quite unlikely so even with 20 trials, there's still a pretty good chance that you will never roll a pair of sixes so 0.569... makes sense.
8. (Original post by Notnek)
That's what I got

If you think about it, 1/36 is quite unlikely so even with 20 trials, there's still a pretty good chance that you will never roll a pair of sixes so 0.569... makes sense.
Well then I have to do 1-0.569 right?
Thanks so much for the help!
9. (Original post by English-help)
Well then I have to do 1-0.569 right?
Thanks so much for the help!
Yes that's right.

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