Answer :
Create the equations-
adult ticket cost=x
child ticket cost=y
8x+5y=177.5
12x+6y=255
the second equation can be simplified to
2x+y=42.5
y=42.5-2x
Plug it into the first equation
8x+5(42.5-2x)=177.5
8x+212.5-10x=177.5
-2x=-35
x=17.5
Use x to solve y=42.5-2x
y=42.5-36
y=6.5
Adult tickets cost $17.50
Child tickets cost $6.50
adult ticket cost=x
child ticket cost=y
8x+5y=177.5
12x+6y=255
the second equation can be simplified to
2x+y=42.5
y=42.5-2x
Plug it into the first equation
8x+5(42.5-2x)=177.5
8x+212.5-10x=177.5
-2x=-35
x=17.5
Use x to solve y=42.5-2x
y=42.5-36
y=6.5
Adult tickets cost $17.50
Child tickets cost $6.50