Who is 33 out of you both?" or "Who is 33 among you both?"

[tufguy]

If there are two people and one of them is 33 years old however, I don't know who. So, can I ask "Who is 33 out of you both?" or "Who is 33 among you both?"

 

[Skrej]

That's an odd context where you'd have that specific knowledge yet not have their name, but you could say this.

Which one of you is 33 (years old)?

 

[Phaedrus]

If there are two people and one of them is 33 years old however, I don't know who. So, can I ask "Who is 33 out of you both?" or "Who is 33 among you both?"

Another option:

Are you[SUB]1[/SUB] 33, or (are) you[SUB]2[/SUB]?
Is it you[SUB]1[/SUB] who are 33, or (is it) you[SUB]2[/SUB]?

The subscripted numbers differentiating the you's would be unvoiced. In real life, eye contact or gestures would be used instead.