Let the number of blue ribbons Erin has won be represented by \( b \) and the number of red ribbons be represented by \( r \). According to the problem, the relationship between blue and red ribbons is given by:
\[ \frac{b}{r} = \frac{3}{2} \]
This can be rewritten as:
\[ 2b = 3r \]
It's also given that the total number of ribbons won by Erin is:
\[ b + r = 30 \]
Now, we can express \( r \) in terms of \( b \):
\[ r = 30 - b \]
Substituting this expression for \( r \) into the equation \( 2b = 3r \):
\[ 2b = 3(30 - b) \]
Expanding this yields:
\[ 2b = 90 - 3b \]
Adding \( 3b \) to both sides results in:
\[ 5b = 90 \]
Now, divide by 5:
\[ b = 18 \]
Now we can find \( r \):
\[ r = 30 - b = 30 - 18 = 12 \]
So, Erin has won 18 blue ribbons and 12 red ribbons.
To complete the statement:
Erin has won 18 blue ribbons and 12 red ribbons.