There is no exact average number of miles that a person can walk in 30 minutes. The distance that a person can cover in that amount of time will depend on their speed.
The Mayo Clinic recommends that people should aim for 30 minutes of exercise a day. If the exercise cannot be completed in one session, separate smaller sessions can be implemented to reach this goal. Physical activity can include yard work, swimming, biking, rock climbing, dancing or strength training, among other activities that raise the heart rate. Regular physical activity is essential to a healthy lifestyle, and loosing or maintaining weight.