Answer to both parts of the question:
What fraction are herbivores? 5/7
What fraction are carnivores? 2/7
First we know herbivores eat grass and vegetables, we know 2/7 eat grass and 3/7 eat vegetables so 2/7 + 3/7 = 5/7 are herbivores.
Next, we know carnivores eat meat, so how many out of the whole (7/7) are carnivores?
If 5/7 are herbivores, we will take 7/7 minus 5/7 = 2/7 carnivores.
Problem solved!
