On A Need To Know Basis

(I overhear two guys studying. Student #1 is preparing for the final exam, whereas Student #2 took the class the previous semester.)

Student #1: *pointing at study sheet* “Hey, can you tell me what the difference between this and this is?”

Student #2: “You don’t need to know that.”

Student #1: “Umm… it’s going to be on the exam!”

Student #2: *snottily* “Well, I don’t need to know that!”