sinjun | Puzzle

Supply the missing number.


A B_ C_ D 16
A B_ C_ A 10
A B_ D_ B 14
B C_ C_ D 20
6 14 22 ?

16, I think.

Are some of them meant to be 'B_', etc? I didn't find any differences between them.

And now that I look at what each letter stands for, it's all so obvious...

I spent ages (well, a few minutes) working my way through solving that!