Question 492243
150 student tickets, 250 adult tickets

let x=student tickets, y=adult tickets
need 2 equations:
1) 2x+3y=1050
2) x+y=400
substitute: y=400-x into first equation
2x+3(400-x)=1050
2x+1200-3x=1050
-x=-150 => x=150   substitute back into second equation
150+y=400
y=250