This is a "Google Tech Dev Guide: Grow Your Technical Skills…", not a "how to interview" guide. Particularly a "foundations of programming" section, in this case.

I don't know if it's a good interview question or not, but that doesn't mean it's not part of learning programming.

There's more to learning to program than learning to do well in interviews, just like there's more to learning in general than doing well on standardized tests.

I think it's odd that so many immediately jumped to discussing the _interview process_. Google's, or anyone's, interview process may or may not be effective at finding talent or being fair. (I have no particular opinion on Google's, but there's LOTS written on the difficulty of creating a successful interview process for programmers, and various different opinions and approaches).

But why do we in this discussion seem to assume the only point of this Google site is helping people _pass interviews_? It doesn't say that's what it's for at all.

I think it's actually a pretty marvelous free site for learning CS and programming of various sorts, for people of various levels and domains.