"Is your shirt white?"
Translation:Ist dein Hemd weiß?
? You got me confused there... Remember that in German the articles are very important, and we have the masculine, feminine and neuter. So, we can use "Euer" for masculine and neuter, e.g. euer Hund (because Hund is Der Hund, masculine) and for neuter, like: euer Brot (Because Brot, bread, is 'Das Brot'); therefore we use euere for feminine, such as euere Frau - your wife, because wife is feminine (Die Frau). Hope I could help...
No. The following translations are possible.
Ist dein Hemd weiß? (informal, addressing one person)
Ist euer Hemd weiß? (informal, addressing more than one person)
Ist Ihr Hemd weiß? (formal, addressing one or more people)
You might want to give this a thorough read. Note that there's a second page.
I wrote "Ist ihr Hemd weiss?" and Duo said "almost good", the mistake is that when one uses the formal version of "euer" the "I" must be capitalized. But after that I hovered the mouse over "your" in the original sentence and it showed "ihr" and not "Ihr". I'm confused a little bit.