Answer: 11 different rows.
Step-by-step explanation:
As the marbles are identical, we do not really care for permutations (as we can really not difference them)
If we have 5 blue marbles, we have only one combination.
B-B-B-B-B
If we have 4 blue marbles, we have 3 combinations:
B-B-B-B-G, G-B-B-B-B, B-B-G-B-B
This is because the blue marbles need to be next to another blue one, so from here we can do the same analysis.
If we have 3 of them, we have 3 combinations.
B-B-B-G-G, G-B-B-B-G, G-G-B-B-B
If we have 2 of them, we have 4 combinations
B-B-G-G-G, G-B-B-G-G, G-G-B-B-G, G-G-G-B-B
then we have 1 + 3 + 3 + 4 = 11 combinations
