Seven-year-old students at an elementary school were given a 10-yard head start in a race. the graph shows how far the average student ran in 30 seconds. which statements best describes the domain of the function represented in the graph ?

a: 10< _ x < _ 60
b: 7< _ x < _ 60
c: 7< _ x < _ 10
d: 0< _ x < _ 10

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?