Student or Learner
Who of you has made only one mistake?
Who of you have made only one mistake?
has/have refer to "who" or "you"?
Should that be:Who of you has made only one mistake?
Which one of you...?
not a teacher
Ex: Who (of you) has ... ?
Ex: Who (among you) is ... ?
Note, you don't need the words in brackets (...) to express the meaning you want.
Read about the phrase Who of you here I'm making a record of this little exchange because it illustrates a question that comes up frequently--the difference between