Read the following passage and answer the question. 

The narrator of this story is a 12-year-old girl who has gone to London with her mother to visit the dentist. The girl has a tooth filled, and then she and her mother go to a café afterwards. When it’s time to go home, they discover that it’s pouring rain and they have no umbrella. They decide to get a taxi. While they’re watching for a cab, an old gentleman sheltering under an umbrella approaches them. He asks for a favor. The girl’s mother is very distrustful of strange men. The old man explains that he has forgotten his wallet and would like to sell them his umbrella in return for taxi fare back to his home. He explains that it’s a very nice silk umbrella worth twenty pounds, but his legs are weak and he simply must take a taxi home. The mother likes the sound of the deal, but the little girl worries that they’re taking advantage of the old man. The mother offers to simply give him the cab fare, but he insists that they take the umbrella. The transaction is made and everyone is happy. As the mother is proudly explaining the importance of correctly judging people, the daughter notices that the old man has quickly crossed the street and is hurrying away. “He doesn’t look very tired to me,” she said. The mother is displeased. “He’s up to something.” They decide to follow him and find out. They quickly follow him as he rushes through the rainy streets. Eventually they find themselves at a pub called “The Red Lion” and watch through the window as the old man enters and uses the pound note to pay for a triple whiskey.