The ratio of North American butterflies to South American butterflies at a butterfly park is 5:3. There are 30 North American butterflies at the butterfly park. How many South American butterflies are there?

Answer 1

for every 5 NA butterflies, there are 3 SA.

30/5 = 6, so there are 6*3=18 SA butterflies.

Answer 2

What does 6 stand for?