"Ele conhece alguma das duas garotas?"

Translation: Does he know either of the two girls?

[ironyisoverrated]

To use "either" and "two" is redundant. "Either" means one or the other.

[eljaykett]

Why is it garotas and not meninas?

[waldyrious]

Either "garotas" or "meninas" would mean roughly the same in this context. Is there a reason you think "meninas" would be more appropriate?

[Muisje94]

Technically, 'menina' would refer to a child and 'garota' to an adolescent, but that distinction isn't really used any more (at least in Brazil). I'm not sure, but I think 'menina' is the more polite form in Portugal.

[deactivated user]

What's wrong with "Does he know one of the girls?"

[Paulenrique]

The sentence clearly shows that are two girls in total. Your suggestion may involve a higher number,

[CarloGamag1]

From the tone of the voice it is to understand that it is a question. I have asked before how does one understand that we are dealing with a question?

[Ronaldo774509]

I think, the word "either" is completely redundant in this English translation