A group of 10 students went to a football game at their university. They each bought a ticket for $x and spent $20 on a t-shirt. A group of 4 adults went to the same football game and paid five times as much for each of their tickets as each student. The group of adults also bought a long-sleeved t-shirt for $25 each. The group of students spent the same amount as the group of adults. What is the cost of each student ticket? Write and solve an equation to model the problem.