You will have to write a system of equations.
Let x represent the number of child tickets.
Let y represent the number of adult tickets.
Your two equations will be:
5.60x + 9.10y = 1045.10
x + y = 136
This is going to be solved using the substitution method.
x + y = 136
x = 136 - y
Substitute x for 136 - y in the other equation.
5.60x + 9.10y = 1045.10
5.60(136 - y) + 9.10y = 1045.10
Distribute the outside terms through the terms inside the parenthesis.
761.60 - 5.60y + 9.10y = 1045.10
Combine like terms.
761.60 + 3.5y = 1045.10
Subtract 761.60 from both sides to get 3.5y by itself.
3.5y = 283.5
To get y by itself, divide both sides by 3.5.
y = 81
81 adult tickets were sold that day.
