The secretary at a computers company is pregnant! It may have been one of the three partners' fault, or maybe someone else's. If a partner was the guilty party, he knows it... but he doesn't want the others to know it was him.

The three partners agree that they must know whether it was one of them who made the girl pregnant (thus possibly allowing a suit against the company) or if it was someone else.

How can they decide if one of them is to blame, without anybody having to accept being the father, if that was the case?

(Some notes: They might just write on papers either "I DID IT" or "I WASN'T IT", but the handwriting might give the guilty party away. Putting a white or black marble in an urn (white=innocent, black=guilty) might work, but someone could possibly see what color was being put in; also, if the guilty one went first, the second could peek inside and realize the answer. The optimum solution should not require much --or any-- extra equipment, and should "resist" inquisitive partners. And, of course, being all of them quite capable hackers, computers are out of the question!)

Partners Bill, Teddy and Gary sit in chairs a reasonable distance apart. They each hold a common handheld calculator (which is not a computer anyone can hack, and hardly "special equipment" -- almost all grade school kids have one). Bill says: "We will now each enter on our calculators the number of partners we know to be innocent. Then we will copy that number into the calculators' memory, and then erase it from the display, so that no one can look over and see anyone else's number. After each has done that, I will walk around and place each calculator (all with zero on their displays) into a black bag. I will then remove the three calculators from the bag and display the memory of each one. After I examine each one, I will erase its memory, so that no one can come around later and dust them for fingerprints.  If they all say '1', we are innocent. But if one of them says '2', then Monica's future baby was fathered by one of us." 

    

                  

Edited on February 22, 2004, 10:30 am

Posted by Penny on 2004-02-21 18:59:47