Questions & Answers about Трое ждут здесь.
Трое is a collective numeral. Russian often uses collective numerals when talking about a group of people, especially when the noun is not stated.
So in this sentence, трое works like three people / the three of them.
Compare:
- Трое ждут здесь. = Three people are waiting here.
- Три человека ждут здесь. = also correct, but with the noun человека stated explicitly.
A bare три by itself would usually sound incomplete here.
Yes. The implied idea is people.
That is one reason трое is useful: it can stand alone without a noun and still clearly mean three people or the three of them.
So Russian does not need to say люди or человека here.
Because трое refers to more than one person, so the verb agrees in the plural.
- ждут = they wait / are waiting
- singular would be ждёт = he/she/it waits
Even though трое is one word, it still means a group of three, so plural agreement is required.