"Are those old tourists?"
Translation:Azok idős turisták?
"Régi" is not to be used for age. It is used mainly with objects, but you can also say "a régi barátnőm" - "my old girlfriend", meaning long-running or previous. From previous times.
"Idős" is mainly used for the age of people. It is polite. Think "elderly".
The less polite word for age is "öreg". "Old".
That would rather translate to "Are those tourists old?"
I don't recall ever seeing idős before. Where was this word introduced?
It seems to happen in Adjectives 1. Is this here sentence appearing in a lesson before that?
Also occasionally it happens that a word gets skipped as you go through learning the lesson.
Must have been luck of the draw -- I encountered this after Adjectives 1, but not during Adjectives 1. Interesting that it's possible to go through a lesson and still miss the vocabulary. I'll have to re-do that lesson (and possibly others too...).