The depth of a river in June was 4 feet. Later in the summer the depth of the river at the same spot was 3.2 feet. What was the percent of change in the depth of the river?

Solve the problem by making up an equation. a man could arrive on time for an appointment if he drove the car at 40 mph; however, since he left the house 15 minutes late, he drove the car at 50 mph and arrive 3 minutes early for the appointment. how far from his house was his appointment?