Diane will spend more than $31 on gifts. So far, she has spent $18. What are the possible additional amounts she will spend? Use c for the additional amount (in dollars) Diane will spend.
Write your answer as an inequality solved for c.

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?