Lolita despoiled $500 in her saving account that earn 5% compounded annually, she forget about it until 15 years later when she came across an old banks statement. What's the multiplier

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?