"Are you all tired?"
Translation:Seid ihr müde?
I put that too and was marked wrong, but I think that it might actually be correct. Here are some examples from Reverso Context where "alle müde" is used to mean ALL of the people referenced. We don't say "you all" in the sense of "y'all" in Australia. Here it actually means "ALL of you" rather than just being a pronoun phrase for addressing a group of people. That was the way I interpreted this sentence, and I think that "alle müde" should work in that sense.
No, Sie (capital) can also be plural formal (as others on this discussion have pointed out).
I don't currently see any mods explaining why "Sind Sie alle müde?" should be wrong, but I wasn't thinking fast enough to submit it as "should be marked correct" before moving to the next exercise.
"Sind sie müde?" would be translated to "Are they tired?" "Are you all tired?" either means "Seid ihr müde? or "Sind Sie müde?" (the latter being used when talking to several people in the polite form) "Are you tired?" would be "Bist du müde?" or "Sind Sie müde?" (the latter to one person that you speak to in the polite form)
'bist ihr' is incorrect because 'ihr' requires a different conjugation of 'sein'. It flags the 'ihr' rather than the 'bist' because the system checks for correct German before checking whether you've done the assignment, and simply moves left to right. Therefore, it sees 'bist' first and then "knows" 'du' has to go with it.
'bist du müde?' is a valid translation of "are you tired?". I can only speculate as why it was allowed here, although my guess would be it's assuming you read 'all' as modifying 'tired' rather than 'you'—'are you entirely exhausted?'—and accepted it for that. It's incorrect if you're talking to multiple people, however.
Capital letters can be distinguishing in written German. In this case, Ihr with capital I is a polite form of the possessive, i.e., a version of 'your' used with someone you'd address as Sie —to borrow Wiktionary's example, if you were to ask someone you don't know "Where is your car, Mrs. Wagner?", you would say Wo ist Ihr Wagen, Frau Wagner?
(Also, 'mude' isn't a word—what you want is müde; use 'ue' if you don't have a way to create 'ü'.)
As noted above, 'mude' isn't a word—what you want is müde; use 'ue' if you don't have a way to create 'ü'.
More importantly, the combination of 'du alle' doesn't make sense; unlike in English, there are different words for 'you' depending on how many 'you's you're talking to, and 'du' can only be used to address one person. (Perhaps this could be translated with the phrase 'all in'….) You must use 'ihr' or 'Sie' for more than one person.