Prisoner and Hats puzzle (variation)

Prisoner #1 must have a white hat. This is because if Prisoner #1 saw two red hats in front of him, he would know that his own hat was white since there are only three white hats in total. However, since Prisoner #1 knows his own hat color, it means that only one of the hats in front of him is red. This means that Prisoner #1's hat must be white.
  • #1
The Outsider
2
0
Here is a brain teaser I came across recently.

Ten prisoners are arranged single file in a line. They are sorted so that the shortest prisoner (prisoner #1) is in the front, and the tallest prisoner (prisoner #10) is in the back. The are all looking forward (in the direction of #1). They all close their eyes. Another man (not in line) has ten hats, three white and seven red. This man gives each prisoner a hat. The prisoners then put on their hats. The prisoners then open their eyes. They can only see the hat colors of the prisoners in front of them (i.e. Prisoner #6 can see the hats and colors of 1-5, but not 6-10). They cannot see the color of their own hat. The prisoners are aware that there are three white hats and seven red.

Prisoner #5 says: "I don't know the color of my hat."
Prisoner #4 says: "I don't know the color of my hat."
Prisoner #3 says: "I don't know the color of my hat."
Prisoner #2 says nothing.
Prisoner #1 says: "I know what color hat I have."

What color hat did Prisoner #1 have and how did he figure it out?
 
Last edited:
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  • #2
The #1´s hat is:
Red

Logic:
#5 didn´t see 3 white hats. #4 didn´t see 2 white hats. #3 didn´t see 1 white hat. #2 should know that there was no white hats with #2 and #1.
 
  • #3
Red
Logic: #5 didn't see 3 white hats, meaning he saw one of these combinations: RRRR,RRRW,RRWR,RRWW,RWRR, RWRW,RWWR, WRRR, WRRW, WRWR,WWRR.

Of these 11 possibilities, 3 have no pair that #4 would see. In other words, #4 didn't see RWW, RWRW, WWR.

Which means #3 knows the possibilities are: RRRR, WRRR, RRRW, WRRW, RRWR, WRWR, RWRR, or WWRR. Only two of those possibilities have #1 wearing a white hat and both of those possibilities have #3 wearing a red hat. If #3 didn't know his color, then #1 had to be wearing a red hat. Not only is #1 wearing a red hat, but #2 is wearing a red hat, as well.
 

1. How does the prisoner and hats puzzle (variation) work?

The prisoner and hats puzzle (variation) is a logic puzzle that involves a group of prisoners wearing hats with different colors. The prisoners are unable to see their own hat color, but can see the colors of the other prisoners' hats. They must use deductive reasoning to figure out the color of their own hat.

2. What is the objective of the prisoner and hats puzzle (variation)?

The objective of the prisoner and hats puzzle (variation) is for the prisoners to correctly determine the color of their own hat. They must work together and use logic to figure out the solution.

3. Are there any variations of the prisoner and hats puzzle?

Yes, there are many variations of the prisoner and hats puzzle. Some variations involve different numbers of prisoners or different hat colors, while others may have additional rules or constraints.

4. What strategies can be used to solve the prisoner and hats puzzle (variation)?

There are several strategies that can be used to solve the prisoner and hats puzzle (variation). These include identifying patterns, making logical deductions based on the colors of other prisoners' hats, and communicating with other prisoners to gather information.

5. Is there a guaranteed solution to the prisoner and hats puzzle (variation)?

Yes, there is always a guaranteed solution to the prisoner and hats puzzle (variation). With enough logical deductions and communication between the prisoners, the solution can be determined. However, the time it takes to find the solution may vary depending on the difficulty of the puzzle.

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