Question

The ratio of North American butterflies to South American butterflies at a butterfly park is 5:3. The ratio of South American butterflies to European butterflies is 3:2. There are 30 North American butterflies at the butterfly park.
a. How many South American butterflies are there?
b. How many European butterflies are there?

I have not done this type of a math problem before and really don't know where to begin on it or how to figure this out with ratios. Please help

Answer 1

since SA to E is 3:2
let SA be 3x and E be 2x
given E = 30
so 2x = 30
x = 15
So we know there are 3x or 45 South American and 30 Europeans, (note 45:30 = 3:2)

also NA : SA = 5:3
let NA be 5y and SA be 3y
but we know 3y = 45
y = 15
so the number of North American butterflies
= 5y or 75.
(again, note that 75: 45 = 5 :3)

Answer 2

I misread the question.
Should have been North American = 30 , not European.

I also noticed that I answered the same question back in 2014 without making that error,
look at the first of the Related Questions below.