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.