What is illegal, logical, and legal?

After having failed his exam in "Logistics and Organization", a
student goes and confronts his lecturer about it.

Student: "Sir, do you
really understand anything about the subject?"

Professor: "Surely I must.
Otherwise I would not be a professor!"

Student: "Great, well then I would
like to ask you a question.  If you can give me the correct answer, I will
accept my mark as is and go. If you however do not know the answer, I want you
give me an "A" for the exam. "

Professor: "Okay, it's a deal. So what is
the question?"

Student: "What is legal, but not logical, logical, but not
legal, and neither logical, nor legal?"

Even after some long and hard
consideration, the professor cannot give the student an answer, and therefore
changes his exam mark into an "A", as agreed.

Afterwards, the professor
calls on his best student and asks him the same question.

He immediately
answers: "Sir, you are 63 years old and married to a 35 year old woman, which is
legal, but not logical. Your wife has a 25 year old lover, which is logical, but
not legal. The fact that you have given your wife's lover an "A", although he
really should have failed, is neither legal, nor logical."