the first 'tre' must be 'due' otherwise the translation is not well
Could "lui ha vinto due di loro..." also work? instead of using ne?
Yes, duolingo accepted that version.
The correct answers given: "ne ha vinti due" but also "ha vinto due di loro".
Why the difference?
because "ne" refers to plural in this sentense? I think...
I ask about the "vinti" "vinto" difference
I thought it was only when the verb is conjugated with "essere" that the past participle has to agree with the subject. Why can't this be "lui ne ha vinto"?
(American English speaker) ...and also when the direct object pronoun immediately precedes the verb, the past particle agrees with that object.
Lui ha vinto entrambi di loro should be accepted. :p
I think that would be "He has won both of them..."?