To watch the high school play, theatre goers must buy a ticket at the door. The cost of an adult ticket is $10.00, and the cost of a student ticket is $7.50. If the number of adult tickets sold is represented by a, and the number of student tickets sold is represented by s, which expression represents the amount of money collected at the door from the ticket sales?
7.50as
7.50(a + s)
(10.00a)(7.50s)
10.00a + 7.50s