Hi Ravendra Singh,
First of all, a warm welcome to the CodeRanch!
That's an easy one: if you don't want to waste 200-300 us dollars,
you should definitely not appear on the exam
These scores illustrate clearly you are not ready for the exam at this moment. You could appear for the exam and still pass it, but it would be a huge gamble! When you would score 80% on the Enthuware mock exams, you probably have a 99% chance to pass the actual exam. With your current score it's at most 30-40%.
So you need to enhance your java knowledge by going through the resources you have (these books are very good) and write plenty of code snippets to experiment what a small change (e.g. change access modifier of a method) will do with your code, preferrably using just javac/java (and not an
IDE). Practice, practice and practice are the 3 keywords for success! You don't learn a language by just reading a few books, you need to get your hands dirty, very dirty
Based on the results of your first mock exam scores, you probably know which areas/topics you have problems with and should get some extra attention while studying.
Hope it helps!
Kind regards,
Roel