# Probability of rolling to dice

If 2 fair dice are rolled together , what is the probability that the sum will be 9

1)Is the probability 4/36 (1/9); as no. of favorable cases are {(3,6);(6,3);(4,5);(5,4)} ?

2) Or is it 2/36 (1/18); as no. of favorable cases are {(3,6);(4,5)} the reason I am confused is that the question does not state if the dices are distinguishable or not. If they are not distinguishable then the answer should be 1/18 as stated in case 2. Is my understanding correct?

• Hint: in scenario 2, are there really 36 different cases in total? – Moyli Nov 29 '15 at 15:44
• Even if the dice are NOT distinguishable, the probability of $(4,5)$ is $\frac{2}{36}$. – barak manos Nov 29 '15 at 15:48