i throw a dice 5 times,(adsbygoogle = window.adsbygoogle || []).push({});

1)what is the probability that i get the number 6 at least twice?

2)what is the probability that i get the same number at least 4 times?

i know that since i am throwing the dice 5 times i have 6^5=7776 options

now all i need to find out is how many of those options contain 2 or more sixes, adn the same number 4 or more times

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1) the number of options containing 6 twice

i think it would be easier to find the amount that contain 0 or 1 six and subtract.

since 0 or 1 of the rolls must be 6 and the rest must not be 6

1*5*5*5*5 + 5*5*5*5*5 = 3750

giving me the probability 3750/7776=0.482 that i will roll less than 2 sixes

and the probability of 0.518 that i will roll 2 or more

but the answer is meant to be 0.196?? where am i going wrong?

had i used 5*5*5*5*5 + 5*5*5*5*5 =6250 instead of 3750 i would have gotten the right answer, but i doint understand why that is correct.

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2) to get the same number 4 or more times i need to get the same number either 4 times or 5 times

the first number can be any number, the next 3 must be the same as the first and the last must either be the same as the first or different to the first

6*1*1*1*1 + 6*1*1*1*5=36

36/7776=0.0046

but again the correct answer is meant to be 0.02 and i cannot see how,

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# Homework Help: Probability of a dice

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