Answer:
6 batches of orange paint can be made.
Explanation:
2 cups of red paint can go to 6 cups of 1/3 a batch of red paint, and 3 cups of yellow paint can go to 9 cups of 1/3 a batch of yellow paint.
She then combines 6 cups of 1/3 cups of red paint with 6 cups of 1/3 cups of yellow paint. The reason it is not 9 is that she doesn't have 3 extra 1/3 cups of red paint.
6 batches of orange paint can be made, with 3 extra 1/3 cups of yellow paint.