"I have received a pair of them."
Translation:Ne ho ricevute un paio.
Because "pair of them" in this case are of female gender in plural (something like "the two shirt / Le due maglie" )
Ho ricevuto le due maglie. // Ne ho ricevute un paio.
I'm not sure though, if we're translating from the English then there's no way to know whether the arbitrary "them" is masculine or feminine. Besides, "un paio" is itself masculine singular, which led me to believe that "ricevuto" ought to be correct.
I guess it's because "ne" replaces something plural (un paio [di something plural]), so the participle has to agree with whatever its replacing. But like you say, there's no way of telling whether it's masculine or feminine.
Persona 1: Hai ricevuto un paio di libri?
Persona 2: Sì, ne ho ricevuti un paio.
1: Anche hai ricevuto un paio di maglie?
2: Sì, pure ne ho ricevute un paio.
There is currently an error; depending on the gender of the noun you are referring to, "ricevuti" or "ricevute" could be correct.
Ne ho ricevuto un paio is accepted. If I understand above comments correctly this should be an error?
That's what I used. My reasoning was "paio" is masculine. "I have received a pair (of them)." Accepted 3.20.19. Good question.
Just to add a complication the word pair in English is singular, despite being a collecting noun. Hmmm.