Deandra is doing her math homework. out of 24 problems total, she completed the first 12 problems in 1 hour and the last 12 problems in 3 hours. what is the unit rate for all 24 problems?

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?