You could fail seven questions, and still meet the minimum mark required.
Each question is worth 2.5 percent. You can get 8 wrong.
You can miss 10% of questions, or 12 questions
You can get 60 questions wrong and get a 70 percent but if you get 61 wrong you are at a 69.5 percent.
Providing that all the other questions are correct then it is 9 questions
You can get 63 questions wrong and get 70%.
24 of them.
6 questions out of 20 is 30%