Will i lose 10 pounds by doing all this?

Yes. If you keep this up you could lose 10 pounds by the end of the summer, but don't do sit ups. They are bad for your abs and back. Crunches would be better. Every week, you should add at least one minute. If you keep using the same time your body will get used to it and won't burn any calories. Make sure to eat a lot of fiber, too.