What should be permalink?

I need article permalink like this
site.com/12/article-title/ where 12 is article ID.
and cat url like this
site.com/cat/cat-name

What should be permalink to achive this?

 

It is /%post_id%/%postname%/.

 

thanks s_ruben for help. What should be permalink for cat (site.com/cat/cat-name)?

 

But you have to use only one permalink. And the permalink /%post_id%/%postname%/ has to show site.com/category/cat-name.

 

In-fact its working for category too. Its showing word category in the url. I just need to show cat in the url. site.com/cat/cat-name
How to do this?

 

From what seo experts say, it should be %postname%.html