Answer: There are 12 European butterflies.
Step-by-step explanation:
Let be "s" the number of South American butterflies at the butterfly park.
Since the ratio of North American butterflies to South American butterflies at a butterfly park is 5:3 and the number of North American butterflies at the butterfly park is 30, you can write the folllowing proportion:
Solving for "s", you get:
Let be "e" the number of European butterflies at the butterfly park.
Knowing that the ratio of South American butterflies to European butterflies at the butterfly park is 3:2, and since there are 18 South American butterflies, you can write the following proportion:
Solving for "e", you get: