There is no way to lose 25 pounds in 6 weeks, ( not healthy) Perhaps over 3 or 4 months.
you good balanced meals and exercise. Plus unless you are of a really small frame, most body height and wieght charts would not want you at 115 pounds ,
You would need to starve yourself to lose that much in such a short period of time. But even if you could, you really shouldn't. Rapid weight loss is neither maintainable or healthy. See here for more How do I achieve rapid weight loss . The only proper way to lose weight is through a healthy balanced diet with regular exercise.