I wrote "1 grown-up and 2 kids," and it was not accepted. Since "grown-up" and "kid" are accepted elsewhere for "adult" and "child", and since numerals are also accepted elsewhere in place of numbers spelled out in English, I feel this answer should be deemed acceptable.
It could be that, too.
It just depends on which context you imagine it in:
"How many tickets would you like?" "One adult and two children"
"What do you see through the window?" "An adult and two children"
Both translate the same in German, so either should be accepted here - report if not.
Why "eine"? And the voice (female) clearly says "eine", not "ein".
Until now I only encountered "der Erwachsene", never "die Erwachsene". Both the hovering tooltip and the Words tab say "Erwachsene" is masculine. Thanks!
erwachsen "adult, grown up" can be used as a noun but still inflects like an adjective.
It can be masculine or feminine: der Erwachsene, die Erwachsene; ein Erwachsener, eine Erwachsene. Note that the endings will change depending on whether there is a definite or indefinite article in front.
Okay, another problem. "One adult woman and two children" is not considered acceptable. Why can't "eine Erwachsene" be translated as "one adult woman", since "one adult" is gender-neutral, while the German is not? (Granted that "adult woman" is a bit redundant.)