If you roll two dice (a green one and a red one), how many different outcomes are there for that roll? (in other words, how many different combinations could you get on the two dice)?
for each number on the green die you can pair it up with 6 different possible numbers on the red die.
So total combinations is 6 x 6 = 36
As I indicated in my comments, there are not 11 nor 30 but 21 combinations if the die are identical