Plz help me find the remaining ratios!

The pyramid below was dissected by a horizontal plane which shape describes the pyramid horizontal cross section

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?

What expression is equivalent to (84+16)