The Brain Teaser: Scroll Down for your Solution
1. John Peterson was born in Albany in 1938, on a date not divisible by 2, 3, or 5, and in a month that does not contain the letters "e" or "i". When does he become one year older?
2. In a certain village there is a man, so the paradox runs, who is a barber; this barber shaves all and only those men in the village who do not shave themselves. Query: Does the barber shave himself?
1. On his birthday!
2. Any man in this village is shaved by the barber if and only if he is not shaved by himself. Therefore in particular the barber shaves himself if and only if he does not. We are in trouble if we say the barber shaves himself and we are in trouble if we say he does not.