To find out how many students attended the dance, we can set up the following equation based on the information given:
Let \( x \) be the number of students who attended the dance.
The total cost paid by Ava is made up of the rental fee plus the cost per student:
\[ 120 + 2.50x = 325 \]
Now, we can solve for \( x \):
- Subtract 120 from both sides:
\[ 2.50x = 325 - 120 \]
\[ 2.50x = 205 \]
- Now, divide both sides by 2.50:
\[ x = \frac{205}{2.50} \]
\[ x = 82 \]
So, the number of students who attended the dance is 82.