Let's make the price of tickets for adults x and children y, now form an equation
Friday - 55y + 20x = 200
Saturday - 72y + 36x = 306
Now you have to have either the x or the y cancel out, so you have to find the relationship between two of them
I am going to multiply the top equation by 9/5 to cancel out the x
99y + 36x = 360
72y + 36x = 306
Now I am going to multiply the bottom equation by -1
-72y - 36x = -306
99y + 36x = 360
The x cancel out
27y = 54
y = 2
So the price of a child ticket is $2
Now plug 2 into one of the original equations
55(2) + 20x = 200
20x = 90
x = 4.5
The price of an adult ticket is $4.50
