On a fine day, Heather and her husband invited their neighbors (two couples) for lunch at their house. The six of them sat at a round table. Heather tells you the following:
1. Vega sat on the left of the woman who sat on the left of the man who sat on the left of Alice.
2. Eugene sat on the left of the man who sat on the left of the woman who sat on the left of the man who sat on the left of the woman who sat on the left of my husband.
3. Justin sat on the left of the woman who sat on the left of Ridley.
4. I did not sit beside my husband.
What is the name of Heather's husband?
Solution:
If you look at the second statement, we know that six people are sitting around the table in a clockwise order starting with Heather's husband.
The order is
Heather's husband, woman, man, woman, man, Eugene
Because Heather did not sit beside her husband, the situation must be as follows:
Heather's husband, woman, man, Heather, man, Eugene
The remaining woman must be Alice, and combining this with the first statement, we arrive at the following situation:
Heather's husband, Alice, man, Heather, Vega, Eugene
Now looking at the third statement, Justin and Ridley can be placed in only one way, and we know the complete order now:
Heather's husband Ridley, Alice, Justin, Heather, Vega, Eugene
Thus, the name of Heather's husband is Ridley.