I am very weak in solving problem related to probability and permutation and combination. Can you please guide me the good content by which I can understand it better.
Thanks in advance.
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.
You learn to swim by swimming, learn to talk by talking and you learn combinatorics by solving problems.
You can get problems at Art of Problem Solving, try to solve as many "different" problems as you can.
If you need help you know where to get it ;)
May the force be with you!