Final answer:
To determine the number of couples at the dance, we need to set up a system of equations using the given information and solve it.
Step-by-step explanation:
To determine the number of couples at the dance, we need to set up a system of equations using the given information. Let x represent the number of couples and y represent the number of single people.
We know that the total number of people at the dance is 155, so we can write the equation x + y = 155. We also know that the total amount of money raised is $255, so we can write the equation 3x + 2y = 255.
Solving this system of equations will give us the values of x and y, which represent the number of couples and single people, respectively, at the dance.