For a school drama performance, student tickets cost $5 each and adult tickets cost $10 each. the sellers collected $3,570 from 512 tickets sold. if c is the number of student tickets sold, which equation can be used to find the amount of tickets sold of each type?

Derek purchased a new gym membership. it costs him seven dollars a month plus two dollars for every time that he visits the gym. he wants to spend less than 25 dollars a month to visit the gym. write an inequality that models the situation using the variable v for the number of visits per month. also find the maximum number of visits he can make to the gym and still keep his cost below 25 dollars a month.