Because MATH, that's why.

[theweaselking]

You roll two fair 6-sided dice.

One of them is a 6.

What are the odds that the other is also a six?

[Poll #1770498]

Comments

[theweaselking.livejournal.com]

You don't know which is which. All you know is that one of them is a six.

[athelind.livejournal.com]

"The other" means "not that one".

[theweaselking.livejournal.com]

And which one is "that one"? One of the two. Which one? Puzzle doesn't say, so you don't know.

The puzzle is not ambiguous.