If you are talking to someone you are framiliar with, family member, school mate or such, we don't say "вы правы." If it were a girl- Ты права. If it were a boy- Ты прав. Though if it were someone "higher" than you, for respect you would use the formal вы and say "вы правы." Or if you were talking to a few people, kids, or adults, you would say it pluralized too. Yes, "ы" has no english equvilent.