Which of the following situations describes an equilibrium? Which does not? If the situation does not describe an equilibrium, what would an equilibrium look like?

Many people regularly commute from the suburbs to downtown Pleasantville. Due to traffic congestion, the trip takes 30 minutes via highway but only 15 minutes via side streets.

At the intersection of Main and Broadway are two gas stations. One station charges $3.00 per gallon for regular gas and the other charges $2.85 per gallon. Customers can get service immediately at the first station but must wait in a long line at the second.

Every student enrolled in Economics 101 must also attend a weekly tutorial. This year there are two sections offered: section A and section B, which meet at the same time in adjoining classrooms and are taught by equally competent instructors. Section A is overcrowded, with people sitting on the floor and often unable to see what is written on the board at the front of the room. Section B has many empty seats.