How many questions are incorrect with a score of 83 on a 80- question test?
Since the student got 83% correct, the student got 17% incorrect.
17% of 80 is 13.6 incorrect. So there could have been some partial credit
given or else, what is most likely, the score was rounded off.
If 13 questions were incorrect, the score would be 83.75 and if
14 were incorrect it would be 82.5.
If the teacher rounds up with .5 or more, the student missed 14 questions.
But if the teacher always rounds down, the student missed 13 questions.
Edwin