Answer:
175 tickets were sold at the door.
Explanation:
Let x = number of pre-sale tickets.
Let y = number of tickets sold at the door.
Equation for total number of tickets:
x + y = 475
Equation of total price of tickets:
1.5x + 2y = 800
System of equations:
x + y = 475
1.5x + 2y = 800
Solve the first equation for x:
x = 475 - y
Substitute into second equation.
1.5(475 - y) + 2y = 800
712.5 - 1.5y + 2y = 800
0.5y = 87.5
y = 175
Answer: 175 tickets were sold at the door.