I'm going to ask you the same question that the book asked and not tell you the answer immediately. I am curious as to how you think!
I put this out to some of my friends and received some rather creative replies. XD
What do you think is the answer? Who do you think will wash his face?
Coelho:No, the one with the dirty face will look at the other man and assume that he looks like him. And, vice versa, the man with the clean face will see his colleague covered in grime and say to himself: I must be dirty too. I’d better have a wash.’