These puzzles may seem like a waste of time, but they serve a practical function in the US government.
I agree with Greg - 0%. 25% would work if D (or A) was something different. As it is, though, a random choice will give 25% 50% of the time, while 50% will be chosen 25% of the time, so that doesn't work and is essentially paradoxical. Since 0% is not one of the given options, there is a 0% probability of randomly selecting it from the given options, so it works as an answer. Alternatively, we can just say that there is no satisfactory solution due to the paradox, which I guess would be the only solution if the question specified that the answer must be selected from the list. Since it doesn't specify this, I think that 0% is the better answer.
If you can open a box multiple times and still kill the person. you can do it in 36 - 72 hours 10 people open 100 boxes each. (Keep Records) 10 people search 10 each of the 100 of the guy that dies 10 people search 1 each of the boxes of the guy that dies 3 people die in total
Apologies for forgetting to put the answer for the 1000 box puzzle so here its is: you can do it in 12-24 hrs. you make a cube of all the boxes 10 x 10 x 10. You need 30 people. Each employee will open a 100 but not any 100. This is now like coordinates in 3 directions x y and z. (x=left/right, y up/down and z forward backward. So person 1 opens all the boxes that have an x=1 so in other words the first column 2nd person second column etc. people 11-20 open y=1 to y=10 and 21-30 will open z=1 to z=10 Now lets say from x direction person 5 died and y direction no. 2 died and z direction no.9 died. You then have an exact coordinate which box has the real gold. So need 30 people but 3 die.
Took a while, but I finally understood how/why it was better to switch Let's assume the gold bar is in box no. 1 (and only the presenter knows this of course) Also assume that you have an equal chance of picking each box, since you don't know what's inside Scenario A: Pick box 1 (1/3 chance) Presenter opens box 2 or box 3 Either way, you'll be worse off switching Scenario B: Pick box 2 (1/3 chance) Presenter is 'forced' to open box 3 Therefore you'd be better switching boxes Scenario C: Pick box 3 (1/3 chance) Presenter is 'forced' to open box 2 Again you'd be better switching boxes Overall you have a 2/3 chance of getting that gold bar by switching boxes (which is shown in the graphs in post #38)
