Holiday Puzzle Solution


The lights (in order): red, red, blue, green, green

Carlos is color blind.


The color blind person knows exactly which lights are blue. It follows that neither Eddie nor Greg is the color blind neighbor.

Looking at the statements made by Amelia, Becky, and Fran, we can see that it is impossible for exactly one of them to be false. Since only one statement is false, it is not one of those three.

We now know that the third, fourth, and fifth lights are blue, green, and green, respectively. We also know that neither of the first two lights is blue.

We also know that the color blind neighbor is either Diane or Carlos.

Suppose that Diane were color blind. If so, the second light would be green. Since red is used somewhere, the first light would be red, making the statement from Carlos false. We can’t have two false statements. We conclude that Carlos, not Diane, is the color blind neighbor.

Given what Diane correctly stated, we now know that the second light is not green, leaving red as the only option. Given what Carlos incorrectly stated, we know that the first light is not green, leaving red as the only option.

(Note: Carlos thought the first light was green, which is why he thought that his statement was correct.)