The 150 problems are for those people who have some idea of programming already. If you are a beginner then you would need more problems. Also, the 150 problems help you cover all the patterns which are there. If you can't understand the pattern with one problem, you would need to solve more problems for it.
Bro I think you are more smart that you can do any problem on LC by just doing 100-150 problems. For a normal person it requires a lot of practice
The 150 problems are for those people who have some idea of programming already. If you are a beginner then you would need more problems. Also, the 150 problems help you cover all the patterns which are there. If you can't understand the pattern with one problem, you would need to solve more problems for it.