You are rolling two dice at the same time. What is the probability of rolling a sum of 5 or 9?
A. 1/81
B. 1/18
C. 2/9
D. 5/9
The sample space when rolling two dice is 6 x 6 = 36 possible outcomes.
To get a sum of 5, the possible outcomes are:
(1, 4), (2, 3), (3, 2), (4, 1) = 4 outcomes
To get a sum of 9, the possible outcomes are:
(3, 6), (4, 5), (5, 4), (6, 3) = 4 outcomes
Therefore, the total number of favorable outcomes is 4 + 4 = 8.
The probability of rolling a sum of 5 or 9 is 8/36 = 2/9.
So the correct answer is C. 2/9.