THE CONTEST Below are to images of Block the Laser. You can also check out a video by clicking here. I will be providing a series of puzzles one at a time, exclusively on this forum. To solve these puzzles will usually take some kind of epiphany or drastic change in perspective, and may take some group discussion to fully understand the problem. If you have any thoughts, observations, or questions for me or other visitors of this forum, please ask. Now let's start the fun...! 1: You are a terrorist. Osama Bin Laden has just been eliminated, but you and 9 other terrorists are taken as prisoners. You are placed in a confined room. On the wall reads the following: 1. You will soon be forced to line up in a single file, facing forward. 2. At no time will you be allowed to turn your head or communicate with each other in any way. 3. I will mark each of your backs with either an X or an O. 4. You will only be able to see all the marks on the backs of the terrorists in front of you. 5. One by one, I will ask you what is the mark on your back, starting with the person whose back is facing away from everyone else. 6. You must tell me by whispering in my ear. I will then repeat the answer loudly, so all of you can hear. 6. If the answer is correct, you live. If the answer is incorrect, you die. To win a Block the Laser promo code, answer the following two questions: What stratetgy would you come up with to maximize how many you filthy terrorists survive this test, and how many of your lives are guarenteed to be saved? Be the first to post the correct solution and explanation and win a promo code for Block the Laser, a puzzle game that I have designed. If you're unclear about something, please ask. I encourage you to post any general thoughts or observations you might have about this puzzle. Good puzzles have the wonderful attribute of allowing you to face your own prejudgements and false assumptions in a creative environment. Good luck and enjoy!
Well, if the terrorists are smart and/or have seen something kind of similar to this before, than they would: Have the last person in line wait 10 seconds before guessing his letter if the one in front of him has an x, and 5 seconds if he has an o (or vice versa). Everyone but the last guy in line (the 1st person to be asked) would be guarenteed safety. As for the second part, the least number that can be saved is 0, if they can't think of a strategy and all guess incorrectly. (If that last part wasn't what you were looking for, which it probably wasn't, then just explain a tiny bit more and I'll answer )
Ashflow, The second part of my puzzle question was not written correctly and it is now fixed. Thanks for point that out. You answered the first part of the question correctly and I know you would have gotten the second part correct as well. You win! I am sending you the promotional codes for Block the Laser. Even though Ashflow solved the puzzle, I am going keep this puzzle up rather than give you guys a new one as I had planned. I am going to go back and change the puzzle to say something like: 'The terrorists must answer the question in exactly 5 seconds and they answer by pushing one of two buttons. One button read X, the other reads O. When the button is pressed, a robotic voice reads the letter that was chosen.' What this new constraint changes is that now terrorist are unable to communcate with one another beyond the responds, X or O. Ashflow, if you can answer this revised question, I'll give you a promotional code for Block the Laser Extreme, a version of the game that I made for more hardcore puzzle enthusiasts. For everyone else, solve the revised puzzle and win the promotional codes for Block the Laser.
I wonder...since the terrorists were lined up in a single file at first, they have no idea what is one each of their backs. "In other words, at no time while standing in line can terrorists communicate with each other by any means as all other than to hear whether X or O was pressed." BUT the question also states: "After you explain this to the terrorists, you allow them 5 minutes to discuss the situation amongst themselves." Having the 5 minutes to discuss the situation amongst themselves, what sane person wouldn't just ask another 'hey, is that a O or X on my back?' EDIT: After reading through the puzzle again, I realized that what you meant was that they have 5 mins to discuss before being lined in a straight line and the X and O are placed. Here's my solution. Let the value of O be zero and the value of X be one. The terrorist at the end of the line (first one to be asked) will count the values of all the X and O in front of him and if the total is even, he will press O, if it is odd, he will press X. This terrorist will have a 50% chance of answering correctly and surviving. Lucky him. Continuing down the line, each terrorist can figure if he has an X or O by adding up the values of all the X and O in front of him and behind him after hearing the robotic answers, not including the answer of the terrorist first asked and compare his answer to the answer of the terrorist first asked. The total number of X has to be an even or odd number matching the initial even or odd answer given by the terrorist first asked. Phew...I kinda confused myself silly as I was trying to type my thoughts out. So following this, 9 of the terrorists guaranteed to survive with the last 1 having a 50% chance.
Congradulations ***** Congradulations to Ashflow & Kzwen!!! ***** Each of these members has solved the Osama Bin Laden puzzle and have won the promo codes to the Block the Laser puzzle app. I'm going to keep the puzzles coming! My next puzzle is called Swingers Swap, which I made for my wife's genius sister when she was just a kid. Click here to read more.
