# Detective, what is the password?

The police suspect a teenager named Joe of planning to murder his ex-girlfriend's entire family. The evidence is locked in Joe's computer. Failing to hack into the computer, the police find Joe's best friend Billy and gather some information:

1) Joe has put his ex's family members into 2 groups on a whiteboard as below:

Group 1:

Father
Sister
Son
Daughter
Children
Cousin
Nancy (her cat)


Group 2:

Mother
Brother
Boyfriend
Husband
Parent
Sibling
Bobby (her pet snake)


2) Joe has used one of his friends' names as the computer's password. The names are:

• Billy
• Lilly
• Kelly
• Ally
• Nancy

3) Joe has told Billy that his computer's password shares the same attribute that he used to categorize his ex's family.

4) A single failed attempt to login to Joe's computer will cause the computer to reformat, thus losing all the evidence.

It turns out to be a very simple logic and a smart detective quickly solves it and arrests Joe. The question is: what is the attribute Joe used to categorize his ex's family, and what is the password?

EDIT: I should have mentioned that the attribute helps to distinguish the password from the rest of the choice

Hint #1:

The Attribute does not necessarily relate to a word's spelling / length. Even the description of the ex's pet fits into the attribute it shares with the group.

• Sounds like a pretty brutal guy, that Joe ... – Rand al'Thor Mar 25 '15 at 22:12
• Thanks for the edit @randal'thor! Haha no offense to anyone named Joe out there! – Alex Mar 25 '15 at 22:12
• What does "shares the same attribute" mean? – Jack M Mar 25 '15 at 22:13
• @JackM that's why it is a brainteaser! – Alex Mar 25 '15 at 22:18
• take the hard disk out, put it as slave(not master/not boot disk) to another computer and open all files there. If it still asks for a password, get 5 disks, copy his disk completely on the other ones and try each name on each separate disk. 5 names, 5 attempts, easy! :D – Novarg Mar 26 '15 at 8:30

Billy

My explanation:

Group 1 is all names/phrases that can be said without completely closing your mouth/touching both of your lips together. Group 2 is all names/phrases where you are required to touch both of your lips together (M in Mother, B in Brother, the middle "b" in Husband, etc.)

Given this connection, 4 of the 5 names (Lilly, Kelly, Ally, Nancy) match Group 1, while Billy is the only one that matches Group 2. Therefore, being the outlier, Billy must be the password.

• Grrr, I was just typing out this exact answer when your one appeared! +1. The only slight problem is the hint, which mentions that even the pets' descriptions fit. "Cat" fits, and "pet snake" fits, but "snake" by itself doesn't. – BenM Mar 26 '15 at 19:44
• Nicely done! Also @BenM, the hint mention the 'description' not the name itself. – Alex Mar 26 '15 at 19:47
• Awesome riddle! This is such a weight off my mind. I've been trying to work this one out since I saw it pop up yesterday. – NonsenseSynapse Mar 26 '15 at 20:01
• @NonsenseSynapse thanks! I was starting to wonder if it's too boring as there are not many attempts, then yours pop up. I wonder what you've guessed thou, before going into the correct answer above – Alex Mar 26 '15 at 20:18
• @Alex I think it was less of people not wanting to guess, and more of your riddle having a specific enough solution that it's hard to have a guess that matches your criteria, but is still incorrect. As for my process, I had a piece of scrap paper written out with the numerical values of every letter, seeing if there was a pattern there. Before your hint, I was comparing "Father" to "Mother" and "Brother." Since they all contained "ther," I figured there had to be something distinguishing "Fa" from "Mo/Bro, "and also unified "Mo/Bro." – NonsenseSynapse Mar 26 '15 at 20:30