I need help with this plz and this is the thing to the other thing I posted

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?

A10 inch cookie cake is divided into 8 slices. what is the area of 3 slices

Which situation is an example of an observational study?