Which question is statistical? how old is my grandmother? what is the average age of my friends? what are the ages of my friends' grandparents? where did you celebrate your last birthday?

Sophia wrote an equation to represent the revenue of a movie theater for one day. she let x represent the number of child tickets sold and y represents the nunver of adult tickets sold. if a child ticket cost $4, an adult ticket cost $6, and the total revenue for the daybwas $420, which equation could sophia use to represent the number of chikd and adult tickets that were sold?