Is it possible to lose 40 pounds in 20 days with a lot of hard work and a strong diet (if you are 170lb woman), if so, how?

Not healthy: in order to loose 40 lbs in 20 days , you would need to starve yourself. The healthy way to do it is to loose approximately 2 lbs per week , 10 lbs per mo. A very strict diet can deprive you of essential nutrients needed to keep your body healthy

No: No, that is too much too fast. You will harm yourself. You need a rational exercise program combined with healthy eating habits.