If both the red square and the blue square have the same perimeter, and the blue square's dimensions are 5mm and 6mm, and the red rectangle's area is 10mm, what is the dimensions of the red rectangle?

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?