How many question can you miss to get an 80 percent on a 81 question test?

Answer 1

80% of 81 is 64.8. If you can get partial credit on questions, as some teachers and professors give, you must get at least 4/5 of the possible points on a 65th question, basically. Short of that, you need to answer 65 of the questions correctly, so you can only miss 16.