Question 1017420: Two fair sided dice (numbered 1-6) are rolled at the same time. What is the probability the sum of the dice is even or at least one dice is rolled a 4?
Found 2 solutions by Fombitz, richard1234:
Answer by Fombitz(32388)   (Show Source):
You can put this solution on YOUR website! There are 12 possible sums.
6 of them are even.
Even : 2,4,6,8,10,12
3 are divisible by 4.
Divisible by 4: 4, 8, 12
3 are both even and divisible by 4.
Answer by richard1234(7193)  (Show Source):
You can put this solution on YOUR website! By inclusion-exclusion, P(even OR >= one 4) = P(even) + P(>= one 4) - P(even AND >= one 4).
P(even) = 1/2.
P(>= one 4) = 1 - P(no 4's) = 1 - (5/6)^2 = 11/36
P(even AND >= one 4) = 5/36 (only 24, 42, 44, 46, 64 work).
Therefore, the correct probability is 1/2 + 11/36 - 5/36 = 24/36 = 2/3.
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