There are 4 interns at the new government agency. All 4 are comp sci majors. John is the only male. The three girls are all close but secretly like John. Lisa is playing hard to get and hopes John will make a move but could trick John into asking her out. Anne likes John and flirts openly but repeatedly tells everyone she will not date a smoker. Sarah is the smartest out of the bunch and wants John to prove to her that he can fulfill her intellectual needs.

One day John arrives at his computer and there is a post-it note with a heart around it and the following numbers written in it.

546591785

Being that asking any of the girls will dissuade the other two from ever wanting to date him, John must guess who left the message and make a gesture to show he wants to date her.

Who left the message? What does John do?

• Obviously Sarah, since she's the one who wants him to 'prove to her that he can fulfill her intellectual needs', hence the coded message. – Rand al'Thor Nov 13 '14 at 21:07
• This was the question that first brought me to P.SE :-( – Rand al'Thor Dec 3 '14 at 13:55

Anne

The numbers correspond to the keyboard key below-and-to-the-right of it (eg. 5=T, 9=O) and spell out TRY TO QUIT.

• How do we know John smokes? – imallett Nov 10 '14 at 19:22
• @imallett it's implied in the question. I think that's one of those handwavey things – Joe Nov 10 '14 at 19:40
• @Joe for sure. But in these sort of questions, every detail matters. Anne just says she won't date a smoker. John is only a smoker by juxtaposition. – imallett Nov 10 '14 at 20:06
• this answer depends greatly on john being a smoker. curiously, the question never states that he is. it is most certainly not implied. in puzzles like these, every detail matters. – user428517 Nov 10 '14 at 21:32
• @IsmaelMiguel i read that. it does not say john is a smoker. if you said that to me in normal conversation, of course i would assume john is a smoker. but this is a word puzzle where details like that matter – user428517 Nov 11 '14 at 18:51

Disclaimer: This is only posted in a half-serious manner because I was bored and looking for alternative decodings.

The message was sent by:

Sarah, but she's trying way too hard. The message is a two-fold trap designed to let John "prove to her that he can fulfill her intellectual needs." It's far more complicated than it needs to be but Sarah is too much of an intellectual to see that.

The first trap is the simple answer (given by Joe).

By using the adjacent numbers on a QWERTY keyboard, it spells out 'TRY TO QUIT'.

If Sarah sees him ask Anne out, she knows he fell for this trap.

The second is far more convoluted. First we take the numbers in overlapping pairs:

54 46 65 59 91 17 78 85


We then assign each to a letter of the alphabet by mod26 so A=0,Z=25:

CUNHNRAH


Translate that to Morse code:

-.-. ..- -. .... -. .-. .- ....


If you translate that as a binary code, you end up with exactly three bytes:

10100011(163) 0000100(4) 10010000(144)


Again taking the mod26 of those values and assigning letters:

HEO


Now with a simple ROT-4 cipher applied:

LIS


Which is short for Lisa.

If he asks Lisa out, Sarah knows he's smart enough to decipher a ridiculously convoluted code. However, he fails the common sense test because only the brainy one (Sarah) would do something like that.

If he asks Sarah out, he's in for a world of hurt when she decides to keep sending messages like this in the future. He should do himself a favor and find someone else altogether.

• This answer had me laughing all afternoon. Excellent example of why you need to carefully control for variables when creating a puzzle... And keep your respondents from the crack. – Jay Carr Nov 11 '14 at 19:33
• Yeah my first thought was, "It has to be Lisa, as she is the only one who would write a riddle like this, and if it's either of the other girls, they are just going to make John ask Lisa out, ruining their chances." Nice touch on the numerology, too. – Michael Nov 12 '14 at 1:02

I don't understand all the support for the shameless apophenia in the other answers. "TRY TO QUIT"? Weak sauce.

The correct solution is thus:

• observe the absence of 0 in the code, which strongly suggests a numpad-based solution (since the 0 is distinct and separate from all other digits here)

• tracing out the numpad digits in the specified order yields a simple diagram where four letters are distinctly seen: L, I, S, A

• we confirm the correctness of this interpretation by noting that SARAH cannot be encoded in this way, since A would appear appear twice and the two instances would be indistinguishable, and ANNE cannot be encoded in this way because E clearly doesn't appear in the figure

Indeed, it's the coy but non-judgmental Lisa flirting with John, by clearly indicating her name. ♥

John should announce he

can't figure out the note because he uses the Dvorak keyboard layout. Sarah sent the note to test his mental acuity, but using Dvorak makes him enough of a mega-nerd that Sarah (and the other ladies) will openly fall for him.

Of course it means "try to quit" but more along the lines of a stalker's threat. (Seriously, is that really the best that Anne can do?) John needs to get out of there as quickly as possible...do not ask questions, do not look back, leave no forwarding address. In the words of the great philosopher: "You can check out any time you want but you can never leave."

• Her mind was clearly Tiffany twisted. – Floris Nov 11 '14 at 7:36