When I do what the problem statement says, I get 47° for the left angle and 58° for the right one. They are not congruent.
The unit rate is $7.75 because 46.50 divide by 6 is $7.75
The measurement you would need is litres. 1000ml = 1litre^2
Let the price of adult ticket and children ticket be a and c respectively
8a+5c=177.50 -> 24a+15c=532.5
12a+6c=255.00 -> 24a+12c=510
24a+15c-24a-12c=532.5-510
3c=22.5
c=7.5
a=17.5