100 prisoners are each locked in a room with three pirates, one of whom will walk the plank in the morning. Each prisoner has 10 bottles of wine, one of which has been poisoned. And each pirate has twelve coins, one of which is counterfeit and weighs either more or less than a genuine coin. In the room is a single switch which the prisoner may either leave as it is or flip. Before being led into the rooms, the prisoners are forced to wear either a red had or a blue hat. They can see all the other prisoner’s hats, but not their own. Meanwhile a six digit prime number of monkeys multiply until their digits reverse. Then all have to get across a river using a canoe that can hold at most two monkeys at a time. But half the monkeys always lie and the other half always tell the truth. Given that the nth prisoner knows that one of the monkeys doesn’t know that a priate doesn’t know product of two numbers between 1 and 100 without knowing that n+1th prisoner has flipped the switch in his room or not after having determined which bottle of wine was poisoned and what color his hat is. What is the solution to this puzzle?
This was played on the July 18, 2009 edition of Car Talk on NPR and attributed only to “Alan”. If you download the podcast, the puzzler starts at the 36:00 minute mark.