How do you lose 10 pounds in 3weeks if i am 5'7 and weigh 140 pounds?

I say the only way to lose weight is to exercise and eat light. really it works. Start out by walking everyday and give yourself maybe one day off. walking is a great way to tone up and lose weight. Just walk around your block or if you have a tredmill then walk and watch t.v. at the same time. Also drink a lot of water. I also heard that Chinese green tea really works try it for fast results.