I said "The house has three modern bedrooms?" and it was marked wrong. Duo Lingo stated the right answer as "The house has GOT three modern bedrooms?" Why the GOT? It sounds like more correct grammar just to say the house HAS, without the got.
'Got' is very poor English and should be avoided. DL has that wrong. Your response should be accepted although it would probably be better not just to rely upon voice intonation to indicate the question
The poster you're responding to wasn't using "has" as an auxiliary, but as the main verb. "Has [someone] [some item]?" is a legitimate way to inquire about possession in English, but it's also old-fashioned and sounds stilted in American English.