"Are you sick?"
'Ssz' is a double-sz, so it's pronounced like a long 'sz'. If you double a digraph (or a trigraph), you only double the first symbol: cs -> ccs; gy -> ggy; zs -> zzs; dzs -> ddzs; and so on.
You just have to watch out with compound words, like karosszék - armchair, which consists of the parts karos - armed.. erm, "with arms", and szék, chair. There is actually 's' clashing with 'sz'. But since those sounds are difficult to pronounce so closely together, it's mostly spoken as an actual 'ssz' anyway.
It's conjugation! Hungarian is full of that:
- vagyok - I am
- vagy - you are
- vagyunk - we are
- vagytok - you (pl.) are
(The verb "to be" is a bit strange in Hungarian, since "he/she/it is" and "they are" usually aren't translated, but you rather say something around the lines of "A ház zöld" - "The house (is) green".)
You gave a wrong answer but it happened to be only one letter away from an alternative accepted translation. So Duolingo corrected your "typo".
Rosszul vagytok? is accepted (plural you, ti)
Rosszul vagy? Is the main translation here, so the word bank offered "vagy"
Rosszul vagyok? means Am I sick?
I've researched a dictionary and it returns "rosszul" as an adverb which means "badly". Is "rosszul" used like an adjective meaning "sick" commonly? Well, English is not my native language but I can get that somebody who is badly can't mean that one person is sick. On the other hand, I can say too that someone is "badly sick."
Yes, "rosszul vagyok" is commonly used, though it is used as an adverb here, not an adjective. Like if I feel nauseated, dizzy, unwell, something not right. It is similar to the german course's "meinem Kind ist schlecht" where it means that my child is unwell / sick and not that my child is naughty.