The members of the city cultural center have decided to put on a play once a night for a week. Their auditorium holds 500 people. By selling tickets, the members would like to raise $2,580 every night to cover all expenses. Let d represent the number of adult tickets sold at $7.50. Let s represent the number of student tickets sold at $4.50 each. If all seats are filled for a performance, how many of each type of ticket must have been sold for the members to raise exactly $2,850? At one performance there were times as many student tickets sold as adult tickets. If there were 480 tickets sold at that performance, how much below the goal of $2,850 did ticket sales fall?