Learn Spanish (Spain): ¿En qué planta vives?

In Spanish, you can never end a sentence with a preposition like en (in/on). Instead, the preposition must go right before the question word. So, "Which floor do you live on?" is rearranged to "On what floor do you live?" (¿En qué planta vives?).

Doesn't planta usually mean a "plant" like a flower or tree?

Yes, planta means "plant" in nature, but in Spain, it is also the most common word for the "floor" or "story" of a building. You might also hear the word piso used to mean "floor," though in Spain piso often refers to the apartment itself.

The translation says "which", so why does the Spanish use qué instead of cuál?

When asking "which" or "what" directly before a noun (like planta), Spanish uses qué. You typically use cuál to mean "which one" when the noun isn't placed right next to it.

Where are the words for "do you" in the Spanish sentence?

Spanish doesn't use helping words like "do" or "does" to ask questions. The "you" is already built into the ending of the verb vives (you live). Simply adding question marks and changing your tone of voice turns it into "do you live?".