Answer:
0.3333
Step-by-step explanation:
You first need to see how many ways he can roll a sum of 4. There are 12 ways. Treat each face as it's own value. There are 2 of each number on the die, so each face of the die is it's own event.
The 12 ways..
1-2. Rolls a 1 with the one of the 1-faces, then rolls a 3 with either of the 3-faces on the second roll. This counts for 2 different sums of 4.
1 (first 1 face) - 3 (first 3 face)
1 (first 1 face) - 3 (second 3 face)
3-4. He rolls a 1 but it's a different face than the other one than the one he rolled above. This gives us 2 more sums of 4
1 (other 1 face) - 3 (first 3 face)
1 (other 1 face) - 3 (second 3 face)
That's 4 total ways, the same logic will apply for the two 2 faces, and the two 3 faces. Each will have 4 more outcomes, giving us 8 more
There are 36 total outcomes (6*6 = 36), so
P(sum of 4) = 12/36 = 0.3333
