Quo? -> "Where to?" -> The question asks for the place that something is going towards, moving in the direction of. Quo eunt? - "Where are they going?"
Ubi -> "Where?" -> The question asks for the place where something is located, positioned. Ubi sunt? -> "Where are they?"
Unde? -> "Where from?" -> The question asks for the location something comes from, moving away from. Unde veniunt? -> "Where are they coming from?"
Hope this helps.
My initial answer is "Where are they going?" and that seems to work colloquially. If you find out someone is going on a journey, you'd want to ask that. But obviously that was marked wrong.
Is there specificity in the Latin used such that the meaning in English requires the formality of asking to where someone is making a journey?
I just wanted to test if only the prononciation here is incorrect or if it will also accept an incorrect answer.
So I wrote the phrase exactly as the speaker says it:
"Qu itew faci'unt"
And guess what?
It accepted my answer!
Duolingo team, "Qu itew faci'unt" is not a Latin sentence please consider to fix it (both the speaker shouldn't say it like that, and my answer should not be accepted).