Zenbook naming: What does it mean?

I can't for the life of me figure out what all the letters mean in the zenbook names. I figured out that if it starts with 30 it means 13" and 50 means 15", but that's it. Other than that I'm totally lost.

Can anyone decipher it? I feel like I'm wasting a lot of time comparing the Zenbooks by jumping back and forth between the specs. I just don't understand why simple naming is such a hard thing.