answer: Mr. Green wants to go back to his hotel by taxi. #Person1# waits with Mr. Green. They find giving taxi drivers 10% tip is a shared convention in their countries.
documents: #Person1#: Excuse me. What did you say you would like to do, Mr. Green?
  #Person2#: I said I'd better go back to the hotel. I'm meeting someone this evening.
  #Person1#: OK. How are you going back? By bus or taxi?
  #Person2#: I think I'll take a taxi. Do you know where I can get one?
  #Person1#: Oh, just wait by the roadside. I'll wait with you.
  #Person2#: OK. Thanks. Are the taxis in London all yellow?
  #Person1#: Well, some of them are. Is this your first time in London?
  #Person2#: Yes, it is. Do you give extra money to taxi drivers here?
  #Person1#: You mean a tip? Oh, yes. They usually expect about ten percent.
  #Person2#: That's the same in my country.
  #Person1#: Oh, look. Here's one. Taxi!
  #Person2#: Thanks. See you tomorrow.