Let x be the ticket for students and y for adults.
The total number of tickets sold is 105. So:
x + y =105
The total amount of money collected is 360. Students pay $2 and adults pay $4. So:
2x + 4y = 360
We are left with the system:
x+y = 105
2x+4y = 360
We'll use the Addition method and multiply the first equation by -2:
-2x-2y = -210
2x+4y = 360
Adding the equations:
-2x+2x-2y+4y = 360-210
2y = 150
y = 75
x+y = 105
x+75 = 105
x= 30
S= {30,75}