Which subject are these students best? (basic high school statistical question) It's a very basic high school statistical question, but I'm struggling to solve it.
Suppose I have a school with $287$ students and each one made a test with $50$ questions (multiple choice questions with $5$ items each, they have to choose one item in each question). These questions are divided into the following subjects:

Subject A - $8$ questions
Subject B - $6$ questions
Subject C - $10$ questions
Subject D - $6$ questions
Subject E - $6$ questions
Subject F - $14$ questions

We say a student fail the test when he doesn't solve any question.
Then we have the following result:

Subject A - $3$ students failed
Subject B - $16$ students failed
Subject C - $1$ students failed
Subject D - $1$ students failed
Subject E - $8$ students failed
Subject F - $0$ students failed

So how can I compare the performance of the students? In another words, which subject were they best and which one were they worse?
Remark: Each student has only two options: successful or failure, so in this case the overall score in each subject is not important.
 A: You define failure as scoring a zero on the test. Then of course, the students are more likely to score a zero if there are fewer questions. Let us say that a test has $n$ questions, and $5$ options per question. Then the probability of getting all the answers wrong is $(\frac{4}{5})^n$. So the probability of "not failing" is $1-(\frac{4}{5})^n$. So with $n$ questions and $287$ students, we expect that $(\frac{4}{5})^n(287)$ should fail. 
If the students together just put it to chance we expect $(\frac{4}{5})^n(287)$ to fail, but if they do something to sway the probability of getting an answer wrong down, then we should expect less to fail. 
Now I make a suggestion, I will define "better", you need not agree with it but I think it is logical: the subject which is "better" is the subject for which the signed percent error from the expected number of failures is minimum.  When it is maximum that is when it is worse.
$$(\frac{\text{observed}-(\frac{4}{5})^n(287)}{(\frac{4}{5})^n(287)})(100)$$
According to this definition of better/worse if you put the subjects in order of better to worse this is what you get:
$$F,D,C,A,E,B$$
