Two math teachers come together and write math problems about fruit vendors. If Teacher A can write 50 problems in 60 minutes and Teacher B can write 50 problems in 80 minutes, how long would it take them to write 50 problems if they worked together?

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?