When does the museum close?

M: Excuse me. One ticket, please. Do you give students a discount?
W: We do, but the museum will close in twenty minutes. We stop selling tickets at 3:30. It’s 3:40 now.
M: Could you possibly let me go in for a quick look? I can pay the full price.
W: I’ m sorry, I can’ t. And it’ s not really worth it because you won’ t be able to see everything within twenty minutes. You can come back tomorrow morning. The museum opens at nine o’ clock.
M: Well, in that case, I’ll do what you say.