There were only 19 students in the class, so the chances of sharing a birthday were quite small.
One boy said: “I’ll bet you a quarter that two of us here have the same birthday.
I give you my word that I don’t know the birthday of anyone here other than my own.
Nevertheless I’ll bet you as I have said.”
Smulllyan took the bet and lost.
Why?
Source: A mixed bag by R.S. 2016