How much percent gets deducted from a test if you get 1 answer wrong?
Can't possibly answer that unless we know how many questions are in the test.
All depends on how many questions are asked for one, and sometimes questions when you need to explain or elaborate are worth more.
It depends on the total number of questions. Ten questions, miss one, get a 90 percent score. Five questions, get one wrong get an 80 percent score, etc...
Well how many questions were there
It depends on the number of questions. If there's 2 questions, you would get 50%. If there's 100 question, you would get 99%