"The rooms in these hotels are too dirty."
Translation:V těchto hotelech jsou pokoje příliš špinavé.
"Pokoje v těchto hotelech jsou příliš špinavé," was marked wrong. Is it wrong?
It sounds really strange in Czech.
ty pokoje points to some particular rooms
Just: "Ty pokoje jsou příliš špinavé." would be perfectly fine.
ty pokoje v těchto hotelech seems overdetermined. Like if you had a list of dirty rooms in these hotels. But then it would rsther be "tyto pokoje".
Mind you, this (accept "the" or not, require "ten, ty" or not) is a topic of frequent discussions among the native speakers here and it is often very unclear. Perhaps someone else will find your sentence OK. Perjsps as a colloquial pronoun similar to "TO počasí je dneska špatné." instead of "Počasí je dneska špatné."