The members of the city cultural center have decided to put on a play once a night for a week. Their auditorium holds people. By selling​ tickets, the members would like to raise ​$ every night to cover all expenses. Let d represent the number of adult tickets sold at ​$. Let s represent the number of student tickets sold at ​$ 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 ​$​? At one performance there were times as many student tickets sold as adult tickets. If there were tickets sold at that​ performance, how much below the goal of ​$ did ticket sales​ fall?