End of Month Puzzle: Buried in the sand
If any one of them is able to tell the correct colour of his own cap, everyone will be saved.
- All of them know that there are 2 black and 2 white caps.
- They can see the caps of only the people in front of them.
- There is a wall, which you can’t see through.
- Not allowed to talk
- Only 1 chance to speak, and only 1 person can speak.
- Everyone is intelligent.
What students worked out11
Student 11
I think it is impossible
Student 12
I don’t think it’s possible
Student 12
but i’ll try more
Student 12
i think 3 can tell his caps color. how? by seeing 2 is wearing a white cap 2 black & 1 white cap left, He will think it’s a pattern black then white then black again white .
Student 4
I think any one of the people buried under the sand (e.g. the 3 one), should just say “whatever is my cap colour, is my cap colour.”. Then it is still right because whatever his cap colour is, is his cap colour.
That could be one possibility, although I’ll try to look for another
Student 4
I think 1 and 2 can’t tell their cap colour as they have a wall between them, so they can’t see anyone’s cap.
Student 4
I think I found out the answer….I think 3 will tell the colour of his cap. Why and how? 4 is at the very back, so he can see the colour of 2’s cap colour and he can also see a Student 58 bit of 3’s cap colour, so he will know that 3’s cap is black and 2’s cap is white. 4 will remain silent as he knows that that 3’s cap is black and 2’s cap is white, but his cap can be either black or white. After some time, 3 will realise that his cap is black because 2’s cap is white and if his cap is also white, 4 would have known that his own cap is black as there are 2 black caps and 2 white caps, but 4 remained quiet because he still didn’t know if his cap was black or white.
If strategy is unclear I can explain in next class.
Student 12
sir you forgot to mention about the wall
Student 12
yes sir, Student 4 is correct everyone will be saved.
Student 15
sir, I think the last person with the white cap as if they are intelligent the last person with the white cap will see the person in front and then the other person in front to while others can’t see people behind them white is the last person so he will understand the pattern and then name everyone and set everyone free
Student 2
3