Permutations-CombinationsWide- Variety Problems Request

I watched all videos on Permutations and combinations, but I am still having a tough time doing questions. Though the videos are good, there is more needed. More variety of solved questions on the Topic. You may know well, that Permutations & Combinations is a very diverse topic. Plz do this.

I am using NCERT Class 11 Maths book. You can find it easily on the web. Plz refer to Exercise 7.3, 7.4 & Miscellaneous Questions. These questions are tough and varied. I can't figure out what is going on in the questions, even if I get the questions right by using the formulae.