Google's Math Puzzle

An anonymous reader writes "Commuters in Cambridge, Mass., are scratching their heads over signs challenging passers-by to solve a complicated math problem. The mysterious banners are actually a job-recruiting pitch from Google."

Comments

I'm a Reebok Sales Engineer!

[garcia]

NPR is clueless. That's why I am the one getting hired by Reebok! The URL was really 1828675309.com and let you to an OGG of Blink182 singing the standard Reebok commercial. At the end you were asked to go down to Foot Locker and buy a specific pair of shoes. On the bottom of the shoe was a keypad. Once you dialed 1829675309 you were connected with a Reebok HR rep and giving a job at a local Foot Locker.

Job as a Google engineer, sheesh. What a load of crap! Would you like whitener or a pair of extra soft socks with your shoes? Perhaps a Nuggets jersey?

Re:I'm a Reebok Sales Engineer!

[tiled_rainbows]

Dude,
you are lying!

1828675309 is not prime - it is equal to 37 * 49423657.

And they said I was wasting my time learning the 37 times table up that far...

Re:I'm a Reebok Sales Engineer!

[Graff]

The URL was really 1828675309.com and let you to an OGG of Blink182 singing the standard Reebok commercial.

On a side note, someone was very clever over at Cingular.com. The URL 8675309.com redirects you to Cingular's web site. I'm sure that only a small percentage of people have tried that URL but I'm sure that means that hundreds or thousands of people were redirected.

Someone was definitely thinking when they set that up.

Re:I'm a Reebok Sales Engineer!

[jrockway]

try http://www.7427466391.com/

Re:I'm a Reebok Sales Engineer!

[Anonymous Coward]

I usually round the value of e up to 3. This way it is easier to work with and is equal to Pi, which I usually round down to 3.

Make it hard next time...

[Mateito]

Easy peasy japonesy

Re:Make it hard next time...

[ajayvb]

Even easier... http://www.google.com/jobs/ Worked for me. I got through two interviews on the phone before being kicked out.

not that complicated

[CommanderTaco]

about 20 mins worth of programming, and i'm not that smart. it ends up taking you to this page.

Re:not that complicated

[benito27uk]

Or just use Google!

Re:not that complicated

[justkarl]

Do you think that Google will get confused, after the link was put on slashdot? Just think, they're probably up to about 500 hits and climbing by now.

Then they're gonna wonder where all the applications are.

Re:not that complicated

[artemis67]

As you can imagine, we get many, many resumes every day, so we developed this little process to increase the signal to noise ratio.

Yes, that is, until somebody posted your link on Slashdot...

Re:not that complicated

[vchoy]

Quote: As you can imagine, we get many, many resumes every day, so we developed this little process to increase the signal to noise ratio. We apologize for taking so much of your time just to ask you to consider working with us.

Well done, you have successfully increased the noise to signal ratio! :P

Re:not that complicated

[maxwell demon]

I guess they are clever enough to filter out all requests having slashdot.org as referrer.

Re:not that complicated

[grub]

Just think, they're probably up to about 500 hits and climbing by now.

So long as Google's mail servers filter out messages with text such as "g00gl3 r0x0r555 h1r3 m3, f4gg0rzzz!" they've likely just hit double digits.

Re:not that complicated

[Florian Weimer]

about 20 mins worth of programming, and i'm not that smart. it ends up taking you to this page.

This one is actually quite easy. We look for a particular host name in Google's address space. So let's try:

$ host www.google.com
www.google.com is an alias for www.google.akadns.net.
www.google.akadns.net has address 216.239.59.147
www.google.akadns.net has address 216.239.59.99
www.google.akadns.net has address 216.239.59.104
$ dnslog 216.239.59.0/24 | grep '^[1-9][0-9]*\.com.A'
$

Hmm, no luck. What about the /16?

$ dnslog 216.239.0.0/16 | grep '^[1-9][0-9]*\.com.A'
466453.com A 216.239.37.99
466453.com A 216.239.39.99
7427466391.com A 216.239.53.184
466453.com A 216.239.57.99
$

Well, we have a candidate, and it is indeed the correct one.

Once you have that domain name, you can search for more information.

Re:not that complicated

[robslimo]

I don't suppose the referrer field that says "slashdot.org" that all the browsers will passing out like bus tokens will cause any notice at google, eh?

Nah, they'd have to be pretty web-savvy to notice that.

Re:not that complicated

[div_2n]

Presumably they are looking for geeks to apply. They put that out there and it gets posted to Slashdot (which they probably expected) and gets deciphered in less than 20 minutes or so (which they also probably expected) and inevitably results in lots of geeks pondering applying to Google.

Sounds reasonable and gets them good exposure at the same time. There is a reason why Google is a household name. This is one more example.

Re:not that complicated

[meringuoid]

Interestingly, that's not cheating. That's exactly what Google are probably looking for. You didn't go charging through millions of digits of 'e' to find the answer; instead, you went looking for any long numerical URLs registered by Google.

That's a much more efficient search strategy. Just what they're after, methinks.

Re:not that complicated

[gowen]

Nice idea, except if you've only seen the billboard, how do you know it has anything to do with Google?

Re:not that complicated

[Skraggy]

I used an even more twisted form of efficiency, I used parallel research, I looked for the answer on Slashdot. Took very little effort on my part, and got me the correct answer on the back of others.

I guess I must be perfect CEO material.

Re:not that complicated

[Council]

Though there's no need to go churning through millions of digits. The density of primes among intergers is roughly 1/ln(n), so one in every 40-odd 10-digit numbers is prime. And indeed, the prime in question appears at about the 100th digit. Not that far in.

So the strategy of searching the digits of e is pretty quick. Even without knowing much perl and having to look things up a lot, I did it in a matter of minutes.

Re:not that complicated

[grazzy]

References: I read slashdot.

Re:not that complicated

[davorg]

how do you know it has anything to do with Google?

You don't need to know that. Here's how I solved it when I first heard about it in July.

#!/usr/bin/perl

use Net::DNS;

my $res = Net::DNS::Resolver->new;

my $e = '2718281828459045235360287471352662497757247093699 9'
.'59574966967627724076630353547594571382178525 166427'
.'427466391932003059921817413596629043572 90033429526'
.'0595630738132328627943490763233829 8807531952510190'
.'11573834187930702154089149934 884167509244761460668';

foreach (0 .. length $e) {
my $n = substr $e, $_, 10;
my $q = $res->search("$n.com");

if ($q) {
print $n, "\n";
last;
}
}

Re:not that complicated

[smaksly]

You get 466453 if you type google on a phone keypad.

Re:not that complicated

[Phisbut]

It's also clear that during the interview process, they're gonna ask people how they found the answer. If you can detail your calculations or reasoning, you're in; if you say "I Googled the question and found the answer...", they'll say "Well, thanks for the flattery, but get the hell out"

Re:not that complicated

[Tablizer]

I took the other route: paid an Indian PhD 50-cents to solve it for me. In case you call it cheating, that better reflects the (new) reality of the work world anyhow: Brains are a cheap global commodity. They should put up a people-skills test instead.

Re:not that complicated

[Florian Weimer]

Nice idea, except if you've only seen the billboard, how do you know it has anything to do with Google?

Good point, but the Google hint just makes it possible to use a more selective index. It's not required, strictly speaking.

If you haven't got this piece of information, you run into another problem: false solutions. In turns out that there is more than one ten-digit domain.

For example, how would you know that this site is the wrong one?

Re:not that complicated

[ePhil_One]

It's also clear that during the interview process, they're gonna ask people how they found the answer.

I used outside the box reasoning to devine the answer. This is a very desirable trait. I'd also point out that my solution was far more efficient than the one my so called competition utilized, and after all don't they want someone who can find the fastest, most efficient, solution?

Now, who can help me with part two

The answer to this equation as the password.

f(1)= 7182818284
f(2)= 8182845904
f(3)= 8747135266
f(4)= 7427466391
f(5)= __________

Re:not that complicated

[JPDeckers]

5966290435

Re:not that complicated

[UnanimousCoward]

I think you're missing the point, which is:

increase the hype by veiling it as an elite problem...

---

Re:not that complicated

[parkrrrr]

You google for "digits of e" and select the second result.

Re:not that complicated

[bob_jenkins]

Oh. My strategy was to google for "consecutive digits of e prime". Google told me the answer, that the site pointed to another site, and that it was in the end an ad for Google engineers. I mighta switched to Teoma once I saw Google was involved, I don't remember.

What I want to know is the point behind that other billboard on 101, the one that says "Applications extreme makeovers TENFOLD HOTTER THAN HELL" and has a picture of a hairy pig wearing sunglasses and a scarf. I was guessing it was associated with the digits-of-e billboard, because both so completely fail to communicate anything useful to the passing motorist.

Re:not that complicated

[andy@petdance.com]

Because 2147483647 is the square of 46341.

No it's not. Squares can only end in 0, 1, 4, 5, 6 or 9.

Re:not that complicated

[gowen]

I know. Thats what you get when you miscopy the number into Mathematica. I'll get my coat.

Re:not that complicated

[kelzer]

ROFL. Somebody please mod parent up. That's so funny.

Never use a $4 calculator when you can use a $1600 software package instead (and then make an invalid conclusion because it rounded off for you!).

Re:not that complicated

[liamo]

Or you could copy e to 10,000 places

Re:not that complicated

[humphrm]

Here's a supposedly true story I heard in some class years ago - probably dynamics or physics or organic or something...

A physics teacher gives each student a barometer, and tells them that using only the barometer and brief visits to the town's tallest building, they have to determine the height of the building. Grades would be awarded based on the most creative solution.

One student started at the top, took a reading, moved to the ground floor, took a reading, and then based on that information and the barometric pressure that day, determined the approximate height of the building.

Other students basically copied the first, although with different variations (bottom to top, etc)

The student who received the only A? He went to the basement. Found the building engineer's office. Knocked on the door. Told the guy who answered, "I have a fine barometer. If you tell me exactly how tall this building is, it's yours."

Re:not that complicated

[rsd]

The sum to all digits turns to be 49.

there is no function to it.

The variable in f(x) as f(1), f(2) is the x position of a ten digit number that sums to be 49.

With a tiny perl program it turns to be: 5966290435
This is in position 128 in the exp(1) number.

Re:not that complicated

[spoonyfork]

I'm curious what sort of person can do this

I'm not the original poster but I did solve the puzzles this afternoon without "cheating". I'm a psychology/philosophy major that hasn't seen a math book in 10 years and I was able to figure it out. What I find interesting is that the answer to the first question (at least how I solved it) was an indirect hint at how to solve the second puzzle. Good luck, it was fun to work through it.

Re:not that complicated

[Anonymous Coward]

Add the digits, beeyotch!!! Those are the first four 10 digit segments of e that add up to 49. They're looking for the fifth. Dumbass. I'm only 8 years old and I figured that out in approximately .1415 nanoseconds.

Love, Will Hunting.

Re:not that complicated

[arose]

/. raising the noise to signal ratio since 1997

Re:not that complicated

[EngMedic]

this story has been around a long, long time -- i heard it first in AP Chem in high school. google for it, but the "traditional" text generally credits neils bohr as being the student :

Sir Ernest Rutherford, President of the Royal Academy, and recipient of the Nobel Prize in Physics, related the following story:

Some time ago I received a call from a colleague. He was about to give a student a zero for his answer to a physics question, while the student claimed a perfect score. The instructor and the student agreed to an impartial arbiter, and I was selected.

I read the examination question: "Show how it is possible to determine the height of a tall building with the aid of a barometer."

The student had answered: "Take the barometer to the top of the building, attach a long rope to it, lower it to the street, and then bring it up, measuring the length of the rope. The length of the rope is the height of the building."

The student really had a strong case for full credit since he had really answered the question completely and correctly! On the other hand, if full credit were given, it could well contribute to a high grade in his physics course and certify competence in physics, but the answer did not confirm this.

I suggested that the student have another try. I gave the student six minutes to answer the question with the warning that the answer should show some knowledge of physics. At the end of five minutes, he hadn't written anything. I asked if he wished to give up, but he said he had many answers to this problem; he was just thinking of the best one. I excused myself for interrupting him and asked him to please go on in the next minute, he dashed off his answer, which read:

"Take the barometer to the top of the building and lean over the edge of the roof. Drop the barometer, timing its fall with a stopwatch. Then, using the formula x=0.5*a*t^2, calculate the height of the building."

At this point, I asked my colleague if he would give up. He conceded, and gave the student almost full credit. While leaving my colleague's office, I recalled that the student had said that he had other answers to the problem, so I asked him what they were.

"Well," said the student, "there are many ways of getting the height of a tall building with the aid of a barometer. For example, you could take the barometer out on a sunny day and measure the height of the barometer, the length of its shadow, and the length of the shadow of the building, and by the use of simple proportion, determine the height of the building."

"Fine," I said, "and others?"

"Yes," said the student, "there is a very basic measurement method you will like. In this method, you take the barometer and begin to walk up the stairs. As you climb the stairs, you mark off the length of the barometer along the wall. You then count the number of marks, and this will give you the height of the building in barometer units. A very direct method."

"Of course. If you want a more sophisticated method, you can tie the barometer to the end of a string, swing it as a pendulum, and determine the value of g [gravity] at the street level and at the top of the building. From the difference between the two values of g, the height of the building, in principle, can be calculated."

"On this same tack, you could take the barometer to the top of the building, attach a long rope to it, lower it to just above the street, and then swing it as a pendulum. You could then calculate the height of the building by the period of the precession."

"Finally," he concluded, "there are many other ways of solving the problem. Probably the best," he said, "is to take the barometer to the basement and knock on the superintendent's door. When the superintendent answers, you speak to him as follows: 'Mr. Superintendent, here is a fine barometer. If you will tell me the height of the building, I will give you this barometer.'"

At this point, I asked the student if he really did not know the c

Dangerous?

[Alizarin Erythrosin]

I hope that drivers who see that can still pay attention to the road. Regardless of whether they are trying to think about it or not.

Re:Dangerous?

[AndrewHowe]

Well, I'm a programmer, and while I start ordinal numbering from 0, I start cardinal numbering from 1... Like everyone else. What's the declaration of the typesOfPeople array? How many elements are in it? 2. Or 10 in binary. How many elements are there in your empty set? -1?

I wonder

[PhysicsGenius]

if it would be acceptable to hack a whois database to see what domains are registered to google.com and just go there without solving the math problem. In fact, maybe they'd prefer that way, since Google has nothing to do with prime numbers but everything to do with the Internet.

Re:I wonder

[rusty0101]

I presume that would work for billboards where 'Google' is prominently displayed somewhere on the billboard. From the images I have seen of the billboards, it ain't there.

Given a Billboard where the only content is a text string '{first 10 digit prime in e}.com' there are three ways to find out that it is a 'google' ad.

1. Solve the puzzle.
2. Bribe the billboard owner. (surely you have seen this billboard advertizing itsel out at one time or another.)
3. Wait till the news breaks that it is a Google Job offer.

Something tells me that Google is more interested in people who quickly solve #1, vs people who can handle #2, or wait for #3.

-Rusty

Re:I wonder

[NoMoreNicksLeft]

I actually figured it out the hard way (still cheated, used online resources to check e versus primes).

The second puzzle, at that site, is really stumping me. If there is indeed a third, I don't stand a chance.

More details on Google's Blog

[GillBates0]

Accessible in their 07/01 archives

Monday, July 12, 2004 Warning: We Brake For Number Theory
If any Silicon Valley drivers have found that traffic is moving more slowly than usual these days on the southbound 101 right around Ralston, you may have us to blame. Last week we unveiled a billboard that's a bit unusual in that it promotes Google only to one very narrow constituency: engineers who are geeky enough to be annoyed at the very existence of a math problem they haven't solved, and smart enough to rectify the situation.

Google Billboard

In other words, the billboard (which offers problem-solvers the URL to, sorry, a page containing an even harder problem), is a recruiting campaign. We've always worked hard to hire the smartest engineers we can find, and we thought this would be a cool way to find a few more. Perhaps including you. If you're a math or computer whiz who doesn't happen to live within shouting distance of Palo Alto -- good luck, and we're looking forward to hearing from you.

- A. Googler

Re:More details on Google's Blog

[Maagma]

Direct Blog Post [google.com] link to Google's hiring campaign market thingy. Ya.

Been done before.

[rritterson]

This is at least the second time google has done this. The first was on a billboard along US 101 in Silicon valley. /. may have covered it then, but I can't find the article so here is one from news.com (note that the caption to the picture if you read the NPR article also references the same billboard.)

This was posted before...

[Anonymous Coward]

I don't have the Slashdot link, but here's the linked-to article the last time around: (beware of Slashdot induced spaces in the url).

http://news.com.com/Google+recruits+eggheads+wit h+ mystery+billboard/2100-1023_3-5263941.html?tag=nef d.pop 2004-07-13 10:33:02
In a kind of geek "Jeopardy," the billboard read:"{first 10-digit prime found in consecutive digits e}.com." The answer, 7427466391.com, would lead a puzzle-sleuth to a Web page with yet another equation to solve, with still no sign the game was hosted by Google.

Mastering that equation would lead someone to a page on Google Labs, the company's research and development department, which reads: "One thing we learned while building Google is that it's easier to find what you're looking for if it comes looking for you. What we're looking for are the best engineers in the world. And here you are.

"As you can imagine, we get many, many resumes every day, so we developed this little process to increase the signal-to-noise ratio."

Frustrating

[ajs]

I spent two days on the second puzzle (the number from e just leads you to a site with the real puzzle), only to realize that the answer was far, far simpler than I had been looking for. I think buildings two blocks down heard the "Doh!" ;-)

A hint for those who want it...

If you're searching through all of your number theory memories and reference texts for a solution, you've left the solution far behind.

Re:Frustrating

[ajs]

BTW: ITA Software has some really good programming puzzles if you're looking for something that's a real challenge. If you're an admin, and you submit a resume for that job we send you a different, more ops-oriented puzzle that you might enjoy.

Is that a hard puzzle

[gowen]

... in the mathematical sense? It strikes me that it probably isn't, since the decimal expansion of e is base dependent, and most "interesting" properties of number are not, IMHO, dependent on the number of fingers our forefathers used for counting.

Is there any method for the solution besides a brute force search and an efficient algorithm for primality testing?

Of course...

[Realistic_Dragon]

...you could just google for the answer:

7427466391

Now, is that a better or worse answer than figuring it out yourself?

Re:Of course...

[redherring22]

look at the source for 7427466391.com... lest you think google would give you some help in their comments, well, all you get is:

<!-- no help here -->

The answer...

[vchoy]

Screw the answer...I just want the job @ colorful Google!!!

Are you trolling?

[mfh]

The URL was really 1828675309.com
That's not resolving and I think I know why...

Jenny, I got your number
I need to make you mine
Jenny, don't change your number
8675309 (8675309)
8675309 (8675309)

I'm a Cheater

[Smuj]

I'm lazy, so I just Googled the answer.

I'm a bit of a maths dunce but

[not_a_product_id]

{first 10-digit prime found in consecutive digits of e}.com

In case you're wondering -- or forgot -- e is the base of the natural system of logarithms, having a numerical value of about 2.71828 (though the number goes on forever).

Get file with copy of prime numbers. Get file with copy of largest precision of e. Use perl to scan for all 10 digit primes and then look for the first one in e.

Profit

or am I missing something?

Re:I'm a bit of a maths dunce but

[samhalliday]

or am I missing something?

yes, the answer...

Re:I'm a bit of a maths dunce but

[Chatterton]

For your reference :)
The fisrt 10 000 digits :P

2.7182818284590452353602874713526624977572470936 99 95957496696762772407663035354759457138217852516642 74274663919320030599218174135966290435729003342952 60595630738132328627943490763233829880753195251019 01157383418793070215408914993488416750924476146066 80822648001684774118537423454424371075390777449920 69551702761838606261331384583000752044933826560297 60673711320070932870912744374704723069697720931014 16928368190255151086574637721112523897844250569536 96770785449969967946864454905987931636889230098793 12773617821542499922957635148220826989519366803318 25288693984964651058209392398294887933203625094431 17301238197068416140397019837679320683282376464804 29531180232878250981945581530175671736133206981125 09961818815930416903515988885193458072738667385894 22879228499892086805825749279610484198444363463244 96848756023362482704197862320900216099023530436994 18491463140934317381436405462531520961836908887070 16768396424378140592714563549061303107208510383750 51011574770417189861068739696552126715468895703503 54021234078498193343210681701210056278802351930332 24745015853904730419957777093503660416997329725088 68769664035557071622684471625607988265178713419512 46652010305921236677194325278675398558944896970964 09754591856956380236370162112047742722836489613422 51644507818244235294863637214174023889344124796357 43702637552944483379980161254922785092577825620926 22648326277933386566481627725164019105900491644998 28931505660472580277863186415519565324425869829469 59308019152987211725563475463964479101459040905862 98496791287406870504895858671747985466775757320568 12884592054133405392200011378630094556068816674001 69842055804033637953764520304024322566135278369511 77883863874439662532249850654995886234281899707733 27617178392803494650143455889707194258639877275471 09629537415211151368350627526023264847287039207643 10059584116612054529703023647254929666938115137322 75364509888903136020572481765851180630364428123149 65507047510254465011727211555194866850800368532281 83152196003735625279449515828418829478761085263981 39559900673764829224437528718462457803619298197139 91475644882626039033814418232625150974827987779964 37308997038886778227138360577297882412561190717663 94650706330452795466185509666618566470971134447401 60704626215680717481877844371436988218559670959102 59686200235371858874856965220005031173439207321139 08032936344797273559552773490717837934216370120500 54513263835440001863239914907054797780566978533580 48966906295119432473099587655236812859041383241160 72260299833053537087613893963917795745401613722361 87893652605381558415871869255386061647798340254351 28439612946035291332594279490433729908573158029095 86313826832914771163963370924003168945863606064584 59251269946557248391865642097526850823075442545993 76917041977780085362730941710163434907696423722294 35236612557250881477922315197477806056967253801718 07763603462459278778465850656050780844211529697521 8908740196

Re:I'm a bit of a maths dunce but

[poot_rootbeer]

Get file with copy of prime numbers. ...all of them?

Interesting

[meganthom]

Personally, I like this approach. Maybe the problem isn't extraordinarily difficult to solve, but the ad itself has a useful purpose for Google's HR department: it finds people who are willing to solve a problem whose solution is not immediately obvious without any immediate gain, other than satisfying their curiosity. That has to be a nice plus for Google. They can limit their hiring process to those individuals and from there give them more challenging problems, take them through the interview process, etc.

Just Google for the answer!

[Zog The Undeniable]

Remember kids, you don't have to KNOW anything any more. This is the age of the search engine.

Re:Just Google for the answer!

[Threni]

> Remember kids, you don't have to KNOW anything any more. This is the age of the
> search engine.

You never had to "know" anything, it's just that it was easier/cheaper/quicker to know something, or employ someone who knew, than it was to look it up. This is increasingly no longer true.

aaah

[gowen]

I hate "what is the next number in the sequence" type puzzles. The correct answer is always the same.

Anything I damn well like. I understand polynomial interpolation

Re:aaah

[BillyBlaze]

He's wrong anyway. Just because any number is a possibility doesn't mean it's the one they're looking for. You have to find a pattern. In this case, the pattern is f(n) = the nth 10-digit block of the digits of e whose digits add up to 49. f(5) is 5966290435. The linux.org login no longer works. And of course, I figured all that out with Google.

Re:aaah

[Jerf]

I think you, and the thread stretching out from your post, are missing the point. The point is not the with polynomial interpolation, gowen can get "the answer". His point is that you can reasonably get any answer.

The set of functions is uncountably infinite. There are uncountably infinite functions that have f of 1, 2, 3, and 4 set to the values Google gave. The reality is that mathematically speaking, giving four numbers results in exactly no constraint on the next number; you might as well just pick one at random. "Polynomial interpolation" is one reasonable path to this, but remember that functions need not even be continuous and are ultimately just infinite look-up tables. (Note the final "solution" is just a lookup table-type function.)

To counter the obvious next objection ("well obviously it is going to be a human-meaningful number"), I take my objection one meta. Obviously we're not truly drawing from that infinite set of functions. However, there's still an effectively infinite set of "human meaningful functions", too. So the true challenge becomes not a math problem, but in sheer guessing which exact constraints the puzzle writer chose.

This is not a mathematical problem. It tries to pretend to be one, but it is not. Generally, once you know the constraints the solution is trivial.

The correct mathematical answer to all such sequences remains "The next number is whatever the hell it feels like being". I have better things to do with my time then try to second-guess somebody pretending to be clever and plucking some random thing out of the uncountably infinite set and demanding that I guess it. Thus, I don't do these puzzles; they're sophmoric in the literal sense of the term, created by people who think they are clever but don't seem to have a deep understanding of math.

People who "solve" the puzzle may impress Google, but I am not impressed by Google using this as a puzzle.

Re:aaah

[Inspector Lopez]

jerf remarks:

This is not a mathematical problem. It tries to pretend to be one, but it is not. Generally, once you know the constraints the solution is trivial.

The correct mathematical answer to all such sequences remains "The next number is whatever the hell it feels like being". I have better things to do with my time then try to second-guess somebody pretending to be clever and plucking some random thing out of the uncountably infinite set and demanding that I guess it. Thus, I don't do these puzzles; they're sophmoric in the literal sense of the term, created by people who think they are clever but don't seem to have a deep understanding of math.

People who "solve" the puzzle may impress Google, but I am not impressed by Google using this as a puzzle.

On the other hand, did Google ever claim that this was a math problem? It is a problem, sure, but it is obviously not a request for a proof of Goldbach's conjecture. Jerf critiques the problem as "sophomoric" but I think that Jerf's complaint is "beating up a strawman" --- he claims that Google posed a math problem and then declares the problem stupid. It is a stupid math problem ... but it's a fun stupid problem.

And, after all, there is a specific set of correct answers, which are perfectly apparent to those who solve the suggested problems --- because they lead to recognition by somebody, perhaps Google --- of particular, quite reasonable answers. If you type in random responses, you're just incredibly unlikely to stumble into the "honeypot."

So (blush, gloat) I have to admit enjoying 45 minutes in the solution of the problems, when I should have been doing what I'm actually supposed to be doing. If only for providing me with 45 minutes of fun, I'm grateful for the problem --- math problem or no.

The quasi-mathematical nature of the problems requires one to either "cheat" by invoking search engines (which, as some have pointed out, may be a perfectly valid solution method as far as Google is concerned), or to demonstrate familiarity with computer tools that facilitate the discovery of the answers.

The very first problem is quite well posed, and if you can figure out how to generate the ten digit numbers, you don't have to look very far. A subsequent problem is very ill-posed (as jerf points out), but nevertheless a "human" is capable of inferring a kind of pattern with far less information than a "mathematician" would consider acceptable. Surely this is precisely the sort of thing that we hope search engines will do for us.

It was fun. Probably Google isn't going to offer me a job, but I had fun. Is that so bad?

E A S Y

[StevenHenderson]

Easy solution:

Use Google to find the solution to Google's puzzle.

Guess they just want people who know how to use a search engine. :)

Hmmm. I went to 42.com...

[jbarr]

...and it just displays some guy's resume. Maybe 42 isn't the answer after all!

Re:Hmmm. I went to 42.com...

[Odin's Raven]

Maybe 42 isn't the answer after all!

Maybe you're just asking the wrong question... ;-)

SPOILERS..

[doowy]

I actually don't want to spoil it, and nobody else should because it is a fun excersise..

I won't post the URL, but here's what it says in case you want a jump on the second question;

Congratulations. You've made it to level 2. Go to www.Linux.org and enter Bobsyouruncle as the login and the answer to this equation as the password.

f(1)= 7182818284
f(2)= 8182845904
f(3)= 8747135266
f(4)= 7427466391
f(5)= __________

Unfortunatley, the fun ends here. When you enter the correct password, you are taken to google lab's hiring page which I presume is accessible without jumping through hoops.

Re:The Answer

[lukewarmfusion]

I saw this on Google Blog a few weeks ago and decided to try it out. Like nearly every problem I encounter, I also check Google for a solution and came up with it right quick. So I'm a little surprised it took so long to make it onto Slashdot.

Anyway, I guess I wasn't paying that close of attention during the IPO thing -

From the Wikipedia article: "In the IPO filing for Google, Inc., in 2004, rather than a typical round-number amount of money, the company announced its intention to raise $2,718,281,828, which is, of course, e billion dollars to the nearest integer."

Why?

[Jodka]

I have heard rumors that Microsoft does something similar, pose math riddles during job interviews.

I suspect these are just ways around the legal prohibitions on testing job candidates. Employers want to identify the smartest job applicants, and these informal riddles allow them to do that legally.

Really really lame

[taybin]

In the latest issue Dr. Dobbs (you get a free subscription if you attend LinuxWorldConf), they had a pullout job application. It was in the style of an SAT test and was filled with such "oh we're so smart and clever and funny and funky funky fresh" questions such as "write a haiku on database caching" and "the box below is empty. fill it with something" and other questions where any of the questions could be considered correct.

It was really annoying. It didn't make me want to work there at all. It was like a "oh we're so smart mensa+masturbating club".

Re:Really really lame

[Anonymous Coward]

Failed it, did you?

Re:Really really lame

[taybin]

Totally. :)

The Answer

[p0]

The digits are 7427466391.

Here is the website which has another puzzle, and it says :

Congratulations. You've made it to level 2. Go to www.Linux.org and enter Bobsyouruncle as the login and the answer to this equation as the password.

f(1)= 7182818284
f(2)= 8182845904
f(3)= 8747135266
f(4)= 7427466391
f(5)= __________

The answer here is 5966290435. This number can also be found in the sequence of 'e'

Spoiler.........

[orion41us]

Answer to 2nd puzzle is @ http://www.mkaz.com/math/google/.......

Why? Isn't there enough road rage already?

[IronChefMorimoto]

Does Google not realize what these billboards are going to do? Think of the poor embattled commuters sitting in suburban to urban traffic clog.

Honking at each other.

Bitching on their cell phones about their wives while pissing off the person(s) behind them who are also on their cell phones bitching about the guy that is jabbering on his phone and not moving forward with traffic.

Bumping each other and causing just enough damage to their cars to NOT really want to risk an insurance claim but also enough to want to get it fixed before the neighbors think they drive a shitty car.

Flipping over and killing each other because one of them thought that he/she had to get to work about 30mph faster than everyone else, because that one person has a much busier day of meetings than everyone else on the highway.

Enter Google -- further frustrating drivers with friggin' math problems on billboards. What? You don't think people will look at them enough to be distracted and frustrated at learning that they're not really Google material?

I call bullshit. 'cause that bitch on the uncontested divorce for $299 billboard torments me every day. Not because I don't like my marriage or want a divorce. No -- she begs the question -- "Can you beat me in court if you want the dog and the 50" plasma TV? Eh, buddy?"

Fuck you lady. Fuck you and your uncontested divorce. And fuck Google for teasing me with a job that I probably will have never known existed if it weren't for people that are actually qualified to answer the math problem having posted the g'damned answers here and made feel stupid as shit.

I'd complain more, but this guy behind me in his gas guzzling SUV is honking at me to move forward one car length while we drive past an accident. Thank god for WiFi in the car. If he honks again, I'm threatening him with the Airsoft 9mm I have in the glove compartment.

IronChefMorimoto

this is old news - and...

[slashpot]

Google sucks ass anyway (not the search engine, working for the company). If you don't want to move to Mt. View California about the only jobs available at their data centers all over America are hardware managers (ooh - order replacement ide drives...) and data center techs. Google is screwing the hell out the data center techs, luring people into quitting stable jobs for a chance to get in the door at Google - using "contract positions" to build the data centers while leading people into thinking they'll get hired on and can climb their ladder to a sys admin position. If you don't believe, me do a quick monster.com search. Guess what happens when the data centers are built and the techies contracts are up... "Don't do evil" my ass.

Picture of Google Billboard

[$exyNerdie]

Here's the Google Billboard picture

(Also note the ClearChannel name at the bottom of the billboard...)

The Answer...

[Paulrothrock]

Can be found out using a relatively short Perl script and some math knowledge.

First, find the first 1, 3, 7, or 9 after the first ten digits after the decimal. Take the preceding 9 digits, and run it through a Prime Number Checker. (The algorithm is in the source).

Really, the hardest part is determining the farthest decimal points of e. Here's the formula: limn->infinity (1 + 1/n)n.

It's lazy, impatient, and full of hubris! BTW, I get a finder's fee.

Google's joke

[$exyNerdie]

This is a joke. Here's why:

Once you solve the billboard puzzle, you get to this page:
http://www.7427466391.com
that has the following text:

Congratulations. You've made it to level 2. Go to www.Linux.org and enter Bobsyouruncle as the login and the answer to this equation as the password.

f(1)= 7182818284
f(2)= 8182845904
f(3)= 8747135266
f(4)= 7427466391
f(5)= __________

NEXT:
You go to http://www.linux.org and enter Bobsyouruncle as the Login name and enter 6969696969 as the password. You get this page:

LOGIN FAILED
Your attempt to login failed for the following reason:
we did not find a matching login/password.

Please Note:
For security reasons, your account will be locked after three login failures. If you have some doubt as to your login name or password, we suggest you go to the account problems page and have your password and/or login mailed to you while your account is still active.
Due to heavy administrative workload, locked accounts may take up to one week to be unlocked.


NEXT:
But if you want to skip that step, you can, because eventual goal is to get you to this web page:
http://www.google.com/labjobs/index.html

SCO's new hiring ad...

[gosand]

SCO has just released a similar billboard puzzle.

1. Sue IBM
2. ???
3. Profit!

If you have the answer to #2, please contact Darl McBride at SCO.com. We have an immediate opening for someone who can solve this riddle.

Re:SCO's new hiring ad...

[grozzie2]

This is to trivial to even consider as a puzzle.

1. Sue IBM
2. Sell Stock
3. Profit!

Nuthin to it, and Daryl has executed step 2 very brilliantly.

It's on Wikipedia since a while...

[flibuste]

You can find the answer on Wikipedia - The Exponential

And it leads to:

However, I found it a nice challenge to take (not too complicated either), and if you get challenged that while working at Google, it must be a pretty interesting job to have.

Welcome aboard!

[MarkGriz]

That's just kind of clever thinking we're looking for. How does a corner office and $150K/year sound?

Re:Welcome aboard!

[grozzie2]

Sounds like a move to an undesirable part of the world, a pay cut, and a requirement to actually commute into somebody else's office. Thanks, but, no thanks.

Google GLAT ( Google Labs Aptitude Test )

[nehumanuscrede]

My last two issues of Mensa Bulletin have come with the same type 'ads / puzzles'. The last issue came with a small ( 21 question ) aptitude test / basic resume type question layout complete with a return envelope.

A few sample questions from it:

#2 Write a haiku describing possible methods for predicting search traffic seasonality.

#4 You are in a maze of twisty little passages, all alike. There is a dusty laptop here with a weak wireless connection. There are dull, lifeless gnomes strolling about. What dost thou do?

A) Wander aimlessly, bumping into obstacles until you are eaten by a grue.

B) Use the laptop as a digging device to tunnel to the next level.

C) Play MPoRPG until the battery dies along with your hopes.

D) Use the computer to map the nodes of the maze and discover an exit path.

E) Email your resume to Google, tell the lead gnome you quit and find yourself in a whole different world.

#9 This space left intentionally blank. Please fill it with something that improves upon emptiness.

#17 Consider a function which, for a given whole number n, returns the number of ones required when writing out all numbers between 0 and n. For example, f(13)=6. Notice that f(1)=1. What is the next largest n such that f(n)=n?

#20 What number comes next in the sequence: 10, 9, 60, 90, 70, 66, ?

A) 96

B) 1 followed by 100 zeros ( a Googol )

C) Either of the above

D) None of the above

#21 In 29 words or fewer, describe what you would strive to accomplish if you worked at Google Labs.

Re:Google GLAT ( Google Labs Aptitude Test )

[AndrewHowe]

Remember last year?
Probably, this year's traffic
Same shape, but scaled up.

Re:Google GLAT ( Google Labs Aptitude Test )

[sgasch]

For #17 first I thought "it will never happen again". Then I thought "if I was really smart I'd prove this mathematically". Then I thought "I can write a 4 line C program to see..." Turns out I was wrong. If you're curious:

1 == 1
199981 == 199981
199982 == 199982
199983 == 199983
199984 == 199984
199985 == 199985
199986 == 199986
199987 == 199987
199988 == 199988
199989 == 199989
199990 == 199990
200000 == 200000
200001 == 200001
1599981 == 1599981
1599982 == 1599982
1599983 == 1599983
1599984 == 1599984
1599985 == 1599985
1599986 == 1599986
1599987 == 1599987
1599988 == 1599988
1599989 == 1599989
1599990 == 1599990
2600000 == 2600000
2600001 == 2600001
13199998 == 13199998
35000000 == 35000000
35000001 == 35000001
35199981 == 35199981
35199982 == 35199982
35199983 == 35199983
35199984 == 35199984
35199985 == 35199985
35199986 == 35199986
35199987 == 35199987
35199988 == 35199988
35199989 == 35199989
35199990 == 35199990
35200000 == 35200000
35200001 == 35200001
117463825 == 117463825
500000000 == 500000000
500000001 == 500000001
500199981 == 500199981
500199982 == 500199982
500199983 == 500199983
500199984 == 500199984
500199985 == 500199985
500199986 == 500199986
500199987 == 500199987
500199988 == 500199988
500199989 == 500199989
500199990 == 500199990
500200000 == 500200000
500200001 == 500200001
501599981 == 501599981
501599982 == 501599982
501599983 == 501599983
501599984 == 501599984
501599985 == 501599985
501599986 == 501599986
501599987 == 501599987
501599988 == 501599988
501599989 == 501599989
501599990 == 501599990
502600000 == 502600000
502600001 == 502600001

Re:Google GLAT ( Google Labs Aptitude Test )

[kent.dickey]

If you go a little higher, you get a fun number:

1111111110 == 1111111110

which is floor((10^10/9) - 1).

Note that since 500,000,001 worked, and 1 works and 500,000,000 has no 1's in it, then any working values from 0-499,999,999 will repeat with 500,000,000 added. After that, the one above is the only one through 2 billion (where I stopped looking).

One-liner Mathematica solution to billboard puzzle

[coult]

I wrote this in a few minutes in Mathematica, and found the answer to the first puzzle. The second puzzle was annoying so I just searched google for it instead.

en = N[\[ExponentialE], 1000]; Table[x = (Floor[en*(10^k)*10^10] - Floor[en*(
10^k)]*10^10); If[PrimeQ[x], {k, x}, {k, 0}], {k, 0, 100}]

Solution

[simgod]

SPOILER

The solutions are:
http://www.7427466391.com/
and:
5966290435

I see their strategy...

[kahei]

...hire only those who like to goof off and write toy programs at their desks instead of doing work... brilliant I tell you brilliant!

Stewie

[Anonymous Coward]

Damn you Tommy Tutone!!

Re:Stewie

[Anonymous Coward]

111-1111... Lois? Damn! 111-1112... Lois? Damn!

Schools

[maggard]

Why Cambridge's Harvard Square? 'Cause it's a popular hangout for students & recently-student folks out for dinner, a show, some shopping (still has a few good bookstores.) Check out this list of area-schools and see why companies retain offices in the area just for recruiting

• Babson College Wellesley
• Bentley College Waltham
• Berklee College of Music Boston
• Boston Architectural Center Boston
• Boston College Newton
• Boston Conservatory, The Boston
• Boston University Boston
• Brandeis University Waltham
• Bunker Hill Community College Boston
• Cambridge College Cambridge
• Emerson College Boston
• Emmanuel College Boston
• Fisher College Boston
• Harvard University Cambridge
• Hellenic College Brookline
• Lesley College Cambridge
• MIT Cambridge
• Massachusetts College of Art Boston
• Massachusetts College of Pharmacy
  and Allied Health Sciences Boston
• Mount Ida College Newton
• New England Conservatory of Music Boston
• New England School of Law Boston
• Northeastern University Boston
• Pine Manor College Chestnut Hill
• Radcliffe College Cambridge
• Simmons College Boston
• Suffolk University Boston
• Tufts University Medford
• Wellesley College Wellesley
• Wentworth Institute of Technology Boston
• Wheelock College Boston

Of course the local hi-tech/biotech/medical/finance/insurance/governme nt industries all also bring in, and offer up, a lot of folks too. I'm only in town part-time but it does make for a heady mix of bright-types.

I used Google to find the answer...

[foistboinder]

Math : Google Labs Problems

When do I start?

Communicating with Math

[stuffduff]

I recently got a new cell phone. I took information for a search and asked for a vanity number. Then I kept hearing the numbers as they told me what was available, checking it and telling them 'no.' Finally on the 11th try I got an acceptible number. What I was searching for was a 7 digit prime. Fortunately the number with area code was the product of two primes as well. Now I can give out either the ordinal index of the prime for the local, or the prime factors of the 10 digit number. People who are unable to deal with the math just can't call me!

A different kind of "smart"

[pauljlucas]

The problem is that the ability to answer such questions has nothing really to do with being able to design or implement good software. I've known several really "smart" PhDs who couldn't code for crap. The problem is they really don't care about code. To them, software design and implementation are merely a means to an end: it's not interesting to them in and of itself. Hence, they never bother to learn to get good at it. They hack together prototypes only to solve the (more interesting) problem at hand. It's some of the most awful code you'll ever see.

Then there are people who are great software designers and implementors who have little ability to solve complex/obsure math problems. Google is throwing all those people away.

Re:Why?

[Jodka]

"What? There's nothing illegal about testing candidates. You can't discriminate on sex or race, but testing skills is totally ok."

It is illegal to give job candidates intelligence tests. So if you want smart employees, you need to find a way around the law.

Legally, the determination of whether you are engaged in discrimitory hiring practices is not based only on your intent. It also includes discrepant impact; If any any test which you administer as part of you job selection process favors a particlar race, then you are guilty of discrimimation. Courts have ruled that tests which measure intelligence are an illegal test for purposes selecting job candidates.

The only exception is that if you can show that that the test specifically measures the skill required for the job. For example, you could give driving tests to drivers. I doubt that if these same math riddles were posed on a written exam that they would pass that legal test for job-relatedness. Google would have to show in court that searching for prime numbers was part of the work that these employees would be expected to do on the job. They ony way employers can get away with this is to pose the same questions informally.

Not at all -- they want the slashdotters too

[xant]

And here's why: The people who did the hard math to solve the problem--hey, they'll make great coders, welcome aboard.

Those of us who googled it or read the /. article successfully got other people to do the work for us, and then took credit for it.

Welcome aboard, manager!

In capitalist USA...

[Mxyzptlk]

employees interview themselves for YOUR company.

Autistic in Seattle

[macmurph]

I saw that bill board in downtown Seattle. My immediate reaction was, "That's dumb... Why would anyone want the URL http://www.7427466391.com/ ?"

San Jose?

[DonGar]

They did this in San Jose a few months ago going North and South on 101. I just assumed it had hit slashdot then and I'd missed the article.

I saw the billboard and decided to solve it. Went googling for a list of pre-computed primes and found the answer already solved instead.

The Google billboard on US Highway 101 in CA

[chongo]

The temperature of Hell is an old physics geek problem. The calculation tale varies, but they state something to the effect that:

The temperature of hell is > 388.36K and < 717.87K because under 1 atm pressure, molten Sulphur (".. into the lake which burneth with fire and brimstone ...") is liquid over that range.

So "TENFOLD HOTTER" would make "extreme makeovers" > 3883.6K and < 7178.7K.

Note that surface of the Sun is usually estimated to be about 5780K which is similar to the midpoint of the hell temperature range (5531.15K).

Therefore one might conclude that these "extreme makeovers" might be brilliant ... thus the need for sun glasses. :-)

I'm sure other interpretations exist.

Google does evil everyday they hire from Stanford

[edgedmurasame]

Well, it probably hurt that you werent some uppity Stanfordite. No wonder you got kicked out. It's one thing to have preference as a person to their college, it's another to base your entire company around the people from there and the practices of said university. Given how Google was, it's no surprise we have some of their side jobs as they are. Uppity people in need of a constant humbling.