If I have a level 10 ram does it mean that it will take a level 10 wall dowe to zero and my troops attack as if there is no wall or do I need more rams?
A level 10 ram? We don't have any worlds with 10-level research (unfortunately).
To answer the question (after testing on .net) you need a minimum of 30 rams and 934 axes (both level 10) - or the equivalent fighting power - to take the wall from level 10 to zero.
There is no set rule for walls vs rams. Attacking a wall with 500 rams and a level 20 wall will work, but if there are 10k spears and 10k swords in that village then i very much doubt the wall will drop much if anything. I think you could say it is subjective. Just try out different amounts and watch the results.