Assuming you mean the sum of the two dice is a Prime number, then:
The possible outcomes are 2, 3, 5, 7, 11 which occur 1, 2, 4, 7, 2 times respectively.
There are 36 possible outcomes
→ pr(prime_sum) = (1+2+4+7+2)/36 = 16/36 = 4/9
If you mean that both dice must show a prime number, then:
The possible primes are 2, 3, 5 → probability of 1 die showing a prime number is 3/6 = ½
→ probability both show a prime number is ½ × ½ = ¼
If you mean either or both dice could show a prime number, then:
The possible primes are 2, 3, 5 → probability of 1 die showing a primes is 3/6 = ½
→ probability of a die not showing a prime is 1 - ½ = ½
→ probability of neither die showing a prime is ½ × ½ = ¼
→ probability of either or both dice show a prime is 1 - ¼ = ¾
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The probability of rolling two even numbers on two standard dice is 0.52, or 0.25.
The probability of rolling the same number on five dice is (1/6)4, or about 0.0007716.
The probability of rolling a sum of 11 with 2 dice is: P(11) = 1/18.For explanation see answer to question: "What is the probability of rolling 7 or 11 with 2 dice?".Read more: What_is_the_probability_of_rolling_7_or_11_with_2_dice
The probability of rolling a 7 with 2 dice is 6/36; probability of rolling an 11 is 2/36. Add the two together to find probability of rolling a 7 or 11 which is 8/36 or 2/9.
The probability of rolling a 4 in a die is 1 in 6, or about 0.1667. The probability, then, of rolling a 4 in at least one of two dice rolls is twice that, or 2 in 6, or 0.3333. The probability of rolling a sum of 4 in two dice is 3 in 36, or 1 in 18, or about 0.05556.