Can i lose 15 lbs in 40 days?

Oh, yeah. That would be easy. If you eat as much as you say you do and exercise the way you do, the weight should be coming off easily. It may slow down a little because your body will not have as much fat to burn off. To lose 15 pounds, I think you should not do the weight training until you get down to your goal weight. Also, you could go down to 110 and still be healthy if you are female. If this is a YMCA you are going to, use the grey machine with orange stripes(don't know the name, sorry). It is extremely low impact and you can burn over 10 calories a minute. Try to avoid carbs and sugars as much as possible. Good Luck!