9 February 2018

# Puzzle time!!

Sitting at the motorbike center (bike getting serviced), I am bored enough to see if I can bore you with one more puzzle to get the weekend rolling ….

There is a contest to judge the smartest couple of them all. Teams of husbands and wives show up for the contest and are soon read out the rules…

Each couple will be taken to a separate room by two officials. Each room will have two tables in diagonally opposite corners. The couple will be separated in the room and asked to go sit at the two tables in the two corners with their backs to each other. From that distance, they will not be able hear or see what is going on in the other table. Under no circumstances can any of the couple utter any sound. If they do, they would be automatically disqualified. Next to each table sat one of the two officials.

The husband and the wife will be given a dice (all dice are perfect dice – one sixth probability for each side). At the sound of a large gong, they will independently roll their own dice on their own table. And note whether they have an even face up or an odd face up. (Odd means 1, 3 or 5). Now, on a piece of paper, each have to write what they think came up on the OTHER table – odd or even. Once both have written their guesses, the two officials will shout out what was written.

If at least one of them guessed correctly about the other table, they continue. If both got it wrong, they will be escorted out of the room and eliminated from the event.

The last couple standing (actually sitting at their tables 🙂 ) wins the event.

So those were the rules.

After all the rules were explained, the officials allowed each couple to talk for a few minutes in case they wanted to come up with a plan and then were escorted to their rooms for the competition to begin.

The smartest couple had devised a way such that they would always win. What strategy did they use?

Note that this is not a trick question like whispering or passing hand messages etc. They were really smart and came up with a way to never get escorted out.

If you know the answer / figured it out, please send me a personal message. I will respond there and also announce your name in the common forum.

Posted February 9, 2018 by rajibroy in category "Puzzles

1. By Rajib Roy on

The logic for the answer is as elegant and is simple. (in fact, I think they almost always go together – simple and elegant).

They have to call Odds or Evens.
While there are 4 possibilities for the husband and wife, this possibilities can be divided into two groups – they get the SAME or they get DIFFERENT. There are no other possibilities.

One of them (let’s say the wife) takes care of the SAME and the other takes care of the DIFFERENT.

So, the strategy they devise is that the wife will see what came up on her dice and then call exactly the same (Odd or Even) for her husband’s dice. And her husband will see what came up on his dice and call the opposite of what he got for his wife’s dice.

That covers all possible possibilities.
BTW, this also means that only ONE of them will right but it is guaranteed that one of them will be right. (They will never be both right or both wrong).

2. By rajibroy (Post author) on

I almost forgot to post the answer.
The logic for the answer is as elegant and is simple. (in fact, I think they almost always go together – simple and elegant).