If i run 3 km four times a week, how long would it take me to lose 10 kg?

Depends on your diet: A pound of fat from a physics viewpoint.Has about 3500 calories. Losing a pound of fat is not the same as using 3500 calories in exercise. Weight loss is the result of using/needing more calories than are taken in by eating. However exercise does not simply withdraw calories from fat cells. A program of weight training, diet management as well as cardio activity can work.