On the first day, 8 adult tickets were sold and 13 student tickets were sold for a total of $75. On day two, 10 adult tickets were sold and 9 student tickets were sold for a total of $72. What is the cost of an adult ticket? What is the cost of a student ticket? Create a system of equations to model the scenario. Determine how the cost of adult tickets and how the cost of student tickets. Use mathematics to justify your answer.