Spoiler If he's blind and we're looking at him from such a distance that he looks like a spot, then he's a blind spot? Edit: never mind. He has not is a blind spot.
<br> Spoiler whoops I missed the part of the original question where the # of barrels had to be = I just wanted to give swoly **** :grin: but alas, I fail
For srrm's eyes, only : Spoiler Are you srrm? Spoiler Are you sure? If yes, click the spoiler. If no, guess on your own. Spoiler You better be. If you lived in Travis County in Aug. 2011, proceed: Spoiler Your edit is the hint here, "has", not "is."
Spoiler Not reading Durvasa's before replying, but I am sure he got it right.. The back man: The fact that he does not answer implies that he cannot tell for certain. Since there is only one way he COULD tell for certain - both men in front of him wearing a white hat - we can safely infer that both men in front of him are definitely not each wearing a white hat. We know this for certain - at least one of the front two hats are definitely black. The center man: the center man knows from the back man's silence that the front two men (including himself) cannot both be wearing a white hat. This means that IF the man in front of him (which he can see) were wearing a white hat, that would necessarily mean that he himself were wearing a black hat. However, his silence implies that he is not sure, and the only way he could not be sure would be if the man in front were wearing a black hat. The man in front: the front man may infer all of the above from the silence of both men behind him, and he may state with certainty that he is in fact wearing a black hat.
It's easier if you think of it in terms of 21 half-barrels, divided by the three sons. Easiest is for one son to get 3 full barrels (x2) and one half-barrel (x1) = 7 halves. Then the other two each take the same - 2 full barrels (x2) and 3 half barrels (x1) equaling 7 halves as well. Ignore the empty barrels altogether.
There is a room with one door but no windows or cracks of any kind for light to escape. There are 3 light switches outside of the room. The door may be opened once but while it is open the light switches cannot be touched. When the door is closed the switches can be flipped. How can a person find out exactly which of the three switches turns on the light. Dumb luck is not an option.
This is an old Google interview question I think. Spoiler While door is closed, turn on switch #1 and leave on for a minute. Then switch it off. Then turn on switch #2 and open the door the one and only time you're allowed. If the light is on then switch #2 is the one that turns on the light. If the light is off but the bulb is hot then switch #1 was the one that turned it on. If neither then it is switch #3.
