In a Memrise course В чем проблема? is translated as "what's the problem?"
Could you explain which case
В чем in in? Проблема looks like Genetive.
Russian Language Stack Exchange is a question and answer site for students, teachers, and linguists wanting to discuss the finer points of the Russian language. It only takes a minute to sign up.Sign up to join this community
The best way to look at this pattern is literally (albeit not too idiomatic) "Wherein lies the problem?"
in what (is) (the) problem?
В чём ра́зница? - what's the difference? Lit: In what does the difference lie?
В чём де́ло? - What's the matter?
В чём беда́? - What's the harm?
В чём я был непра́в? - What was I wrong about?