Joanne puts 40 bacteria in a petri dish. The population of bacteria is doubling every hour. Which function best represents the situation? (TEKS A.9B-5)

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?