Sufficient and necessary condition

Question

The professor tells Samuel: "If you get at least a B on the final exam then you will pass the course." Samuel passes the course. What can he conclude? a. He got at least a B in the final b. He can't conclude anything. Explain your answer

=> I think that he can conclude (a), since getting at least a B is the necessary condition for passing the course. Is that correct?

Answer 1

"He cannot conclude anything." getting at least B is the sufficient but may not be necessary.

you can conclude he pass the exam if he got at least B. But you cannot conclude anything if he pass the exam

Answer 2

it says that if you get at least B you pass the class, but doesn't say if you don't get B.maybe you pass the class with any score, who knows.So it doesn't convey any information what happens when you don't get B.