Okay, after having a go at most of the Lateral Thinking problems posted here I guess it's time to contribute something myself
Let's see how you go with these...Lateral Thinking VIII
25monks live together in a monastery, but because they are very busy they only see each other at dinner which all of them eat together. The specialty of this monastery is that the monks are not allowed to talk-no matter what happens. One day a number of the monks get sick. All of them know that at least one-maybe even all of them, have this illness and that it will have to be treated by a doctor, but only the ones who are sick are allowed to take a day off work to go. The problem is that the only sign of the disease is, that you get purple spots in your face and since there are no mirrors or other reflecting surfaces around, the monks themselves don't know if they are sick or not.
Now this is what happened. All of the monks came to dinner every day, sat down in their usual seat, ate and left again. They didn't use sign language, write notes or communicate in any other way. This continued for a number of days. One day (all on the same day) all of the sick (and only the sick) monks went to the doctor. How did they find out that they are sick?
I should mention though, that all of the monks are really good at lateral thinking.
-the disease does not spread further after the first outbreak.
-A monk will go to the doctor when he knows that he is sick.
(Don't think any of you would get this wrong but just in case: This story is not meant to be religiously offending or anything, I just couldn't think of something else- you could just as well make them little green men or something like that.)Lateral Thinking IX
You are blindfolded and 10coins (all of them are the same) lie in front of you, 5 of them with heads up the other 5 with tails up but they are all mixed up and you can't feel or find out any other way which side is up on which coin.
The task is to make two groups of five coins with the same number of coins with heads up and with tails up in both groups. (You are allowed to turn around the coins of course.)
An example would be having 3coins with heads and 2coins with tails up in each group.
(Heads and tails- the different sides of a coin. The one with a picture-normally a portrait- on it is heads; the other one is tails. It doesn't really matter for this though-you can also imagine them being different colors.)Note: I gave these two and another one (which I might post later on today or tomorrow) to ayw for a consistency check (he actually solved all three within a day-I still can't believe he actually did) because I had to translate them and invented part of the monk riddle and the story for the third one myself (I only remembered the general idea of the original problem, but not the full story). It might be that we still missed something so
Feel free to ask if you don't understand anything - I don't bite EDIT: I've added a couple of logic questions- go and have a look at them on page2.
8.3.09: More added on page3
"It is one of those instances where the reasoner can produce an effect which seems remarkable to his neighbor, because the latter has missed the one little point which is the basis of the deduction."