Answer:
Part a) variable x (the number of adult tickets sold) and variable y (the number of child tickets sold)
Part b) 
Part c) The number of adult tickets sold was 86
Step-by-step explanation:
Part a) Name a variable for the number of adult tickets sold and name a variable for the number of child tickets sold
Let
x -----> the number of adult tickets sold
y -----> the number of child tickets sold
Part b) Write an equation in two variables to model the problem
we know that
-----> equation A
-----> equation B
substitute equation B in equation A and solve for x


Part c) Using your equation in Part B, solve the problem and answer the question "how many adult tickets did Anne sell?" i
we have

Solve for x
Subtract 416 both sides



therefore
The number of adult tickets sold was 86