You and she have finished {your/yours} work?
2 Answers
The correct word in the context you have given is
your
e.g.
You and she have finished your work?
The grammatically correct question is:
'Have you both finished your work?'
Including 'and she' sounds strange.
As about 'yours' it can't be used before nouns.
YOURS is a pronoun and functions as the subject or nominative provocative of the sentence.
For example: 'Is this her work?' - 'No, it's yours.'