Answer:
# of students = 393, # of non-students = 104
Step-by-step explanation:
We have a system of equations (# of students = s, # of non-students = n):
1. Total people attended: s + n = 497
2. Total earnings: 2.5s + 4.5n = 1450.5
We can change the first equation to n = 497 - s, and substitute that into the other equation: 2.5s + 4.5(497 - s) = 1450.5
Expand: 2.5s + 2236.5 - 4.5s = 1450.5
Subtract: 2.5s - 4.5s = 1450.5 - 2236.5
Simplify: -2s = -786
Divide: s = 393
Plug into first equation: 393 + n = 497
Subtract: n = 104
