How much weight will you loose 8 days by starving and also exersizing?

That would be a bad idea. You would be losing muscle from your body using it as food for energy to keep functioning, and you would be losing even more muscle because of the exercise. Don't forget, your heart would be one of those muscles. Working your heart harder as it is getting weaker would be a recipe for death...as if starving yourself wouldn't be asking for death in the first place. Other organs would probably start failing along the way as well.