You might not have missed any - you just got nearly half of them wrong.
You can miss 10% of questions, or 12 questions
1400.
Eight of them.
20
22 questions
35
24 of them.
6 of them.
40
25 questions missed
No more than 15.But why miss any ?
.8 x 30 = 24 so you can miss 6 questions