Riddle time - U2

[klaus]

There are no tricks, this is a straight forward problem.

Allegedly, this is one of the questions for potential Microsoft employees. I must warn you, you can really get caught up trying to solve this problem.

- Reportedly, one guy solved it by writing a C program, although that took him 37 minutes to develop (compiled and ran on the 1st try though).

- Another guy solved it in three minutes.

- A group of 50, at Motorola, couldn't figure it out at all.

See how long it takes you.

Here we go...

"U2" has a concert that starts in 17 minutes and they must all cross a bridge to get there. All four men begin on the same side of the bridge. You must help them across to the other side. It is night. There is one flashlight. A maximum of two people can cross at one time. Any party who crosses, either 1 or 2 people, must have the flashlight with them. The flashlight must be walked back and forth, it cannot be thrown, etc. Each band member walks at a different speed. A pair must walk together at the rate of the slower man's pace:

- Bono: - 1 minute to cross
- Edge: - 2 minutes to cross
- Adam: - 5 minutes to cross
- Larry: - 10 minutes to cross

For example: if Bono and Larry walk across first, 10 minutes have elapsed when they get to the other side of the bridge. If Larry then returns with the flashlight, a total of 20 minutes have passed and you have failed the mission.

Notes: There is no trick behind this. It is the simple movement of resources in the appropriate order. There are two known answers to this problem. This is based on a question that Microsoft gives to all prospective employees.

Note: Microsoft expects you to answer this question in under 5 minutes!

[klaus]

If you have the answer, DON'T post it right away... lets let everyone think about the it for a while. BTW..it took me more then 3 minutes...and then I gave up. I now know the solution.

[Tyson]

I did it and thought I had a minute to spare, but turns out I made it in 17 minutes exactly!!

and it was a couple of minutes to solve it.

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<P ID="edit"><FONT SIZE=-1>Edited by Yota_602 on 04/23/02 05:32 PM (server time).</FONT></P>

[mxjeremy]

DONE. Took me 2 minutes, a pen & paper, I figured out both solutions, and I don't know how you have an extra minute Yota, but PM me with the solution if you do.

I graduated from UCI a couple years ago, and being a Comp Sci, I know a few of Microsoft's interview puzzles, but I have never seen this one before. Lemme know if you want them and I'll see if I can remember them enough to post them up here.

[rdc]

Good one Klaus... I was about to give up then I got it!!!! I got them across in 14 mins.. So does this mean I get the job???

Tony
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[Tyson]

14 minutes. . .WTF. . .I think you may have added it up wrong.


and Jeremy, I thought I had an extra minute but then I looked down at my paper again, needless to say. .but D'OH!!! I still did it both ways in 17 minutes.

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[rdc]

DOHHHH I did it wrong... I guess it is back to the unemployment line!

Tony
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[rdc]

Okay I figured out how to do it.. Yep it is 17 mins

Tony
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[Tyson]

LOL, that is a tricky little riddle.

I got 1 as well.

a farmer needs to get a fox, chicken, and chicken feed across a lake. He has a small boat that only fits him and 1 object across at a time. How does he get all three things across the lake? and how?

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[rdc]

take the chicken across, come back get the fox and take across, return with chicken, leave chicken and take feed across, go back for chicken...

I got one.. How do you unload a 4.0L motor(complete) out of the back of your truck all alone and you have no engine hoist... J/K that is just something I had to do once that really sucked! But I got it done...

Tony
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[Tyson]

There ya go.




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[Kritter]

not bad klaus. i liked that one.

Kris

"A signature always reveals a man's character -- and sometimes even his name. "

[klaus]

Answer for those still confused;

Bono + Edge = 2 = 2
Bono = 1 = 3
Larry + Adam = 10 = 13
Edge = 2 = 15
Bono = Edge = 2 = 17

Job done, they all make the concert and i get the job at M$

[JenDiggityDirt]

The REAL answer to Klaus' questions is: use the flashlight to beat them all until they promise to never ever play any more of their crappy music! The answer to Tyson's questions is: feed the feed to the chicken and the chicken to the fox.

<font color=red>JEN!</font color=red>

[Tyson]

Are you in a bad mood this evening Jen?

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[JenDiggityDirt]

No, i just HATE that horrible band.. And the answer to your question was pure logic at work :) That is the right answer, no?

<font color=red>JEN!</font color=red>

[Tyson]

NO, you were wrong - your pure logic was incorrect. lol

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[Tyson]

farmer takes the chicken across the lake ------------------>

<------------------------------then comes back alone

and gets the fox ----------------------------------------------->

<------------------------then brings back the chicken

and swaps it for the feed, and takes the feed across----->

<-------------------comes back alone to get the chicken

Brings the chicken across the lake---------------------------->

and there ya go!

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[JCA]

HAHAHAHA Tyson you got it wrong too.

farmer takes the chicken across the lake ------------------>

<------------------------------then comes back alone

and gets the feed ----------------------------------------------->

<------------------------then brings back the chicken

and swaps it for the fox, and takes the fox across----->

<-------------------comes back alone to get the chicken

Brings the chicken across the lake---------------------------->

I was sitting on the shore drinking a cold one and watched the whole thing go down. lol


J.C. Andrews
Andrews Racing
www.andrewsracing.com (http://)

[Tyson]

HAHHAHA, I felt pretty dumb there for a second thinking I really did get it wrong. . .lol

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[JenDiggityDirt]

Tyson, last night in chat you explained to me that my answer was wrong because you had specified that the farmer had to get all three things across SAFELY, but allow me to paste to you exactly what you originally typed: ***a farmer needs to get a fox, chicken, and chicken feed across a lake. He has a small boat that only fits him and 1 object across at a time. How does he get all three things across the lake? and how?*** Therefore, my pure logic WAS correct! It may not have been the answer you were looking for, but it still is a plausible solution to the riddle that you posted. It's also the most time-saving solution. So there. Now I have a riddle too! Which weighs more: a pound of feathers or a pound of gold?
P.S. Someone recently said I was "stupid" because of my answer to Klaus' riddle and also said I "ruined" a perfectly good post. Well, upon reflection, I DON'T TAKE IT BACK!!! I really DO despise U2 and I don't care what anyone thinks about it.

<font color=red>JEN!</font color=red>

[Steve_HKmtrsprts]

Come on Jen "Its a Beautiful Day" cheer up!!! http://www.race-dezert.com/wwwthreads/images/icons/wink.gif
I'm with Jen, U2 sux!!!

[Tyson]

k, but just to give you another view of that - ***a farmer needs to get a fox, chicken, and chicken feed across a lake. He has a small boat that only fits him and 1 object across at a time. How does he get all three things across the lake? and how?*** if the chicken eats the feed, and the fox eats the chicken then all 3 things arent really getting across the lake are they? The farmer and the fox in that scenario make it across, but the chicken is dead, and the feed has been eaten. . .It was just a ridlle, and next time I am sure to "SPECIFY" all the details/rules http://www.race-dezert.com/wwwthreads/images/icons/wink.gif. . .lol

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[JenDiggityDirt]

But all three things WOULD be getting across! The feed would be inside the chicken and the chicken would be inside the fox and all three items would technically be across. Stop being so stubborn and tell me I'M RIGHT! :)

<font color=red>JEN!</font color=red>

[Tyson]

BUt that isnt right. If the feed has been consumed then it no longer technically is "feed". and if the chicken has been eaten by the fox, then it no longer is technically a chicken, its DEAD!! So nope, still not gonna tell you your right unless you can convince me otherwise.


LOL

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[frankh]

Jen's answer could be right , just depends on if the fox had time to go to the bathroom before he left.

[JenDiggityDirt]

Good point, Frank! Of course, if the man ate...oh never mind. Tthat's just too gross. Tyson, you did not specify that the items were not to change form, only that all the items had to get across and with my way that is accomplished! TELL ME I AM RIGHT! And isn't ANYONE going to try and answer my riddle?

<font color=red>JEN!</font color=red>

[rdc]

He did specify that the farmer could only take one thing across at a time. So therefore you broke the rules by taking all three at once.. Sorry but you got it wrong.. But what I want to know is why does a farmer have a fox if he raises chickens??? Now thats just looking for trouble..

And Jen they both weigh a pound.. But I would rather have the gold!!!!

Tony
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[klaus]

ok... the U2 question should have been:

"The Trophy Truck drivers" have a Race that starts in 17 minutes and they must all cross a bridge to get there. All four drivers begin on the same side of the bridge. You must help them across to the other side. It is night. There is one flashlight. A maximum of two people can cross at one time. Any party who crosses, either 1 or 2 people, must have the flashlight with them. The flashlight must be walked back and forth, it cannot be thrown, etc. Each TT driver walks at a different speed. A pair must walk together at the rate of the slower man's pace:

- Ed: - 1 minute to cross
- Tim: - 2 minutes to cross
- Robby: - 5 minutes to cross
- Scott: - 10 minutes to cross

[JoshW]

I think you may have those times mixed up. I think it would take the brothers a little longer due to a couple of flats.

[Tim]

so your not left hanging, definately a pound of ... a pound of ... oh yah a pound still weighs a pound even if its feathers, but the gold would be a little nicer to have! tim
p.s. and I uhhhhhh third that! U2 is about as good as Creed! ...I hate them so!!!!!

[JenDiggityDirt]

Okay, Tony, good point. Anyway, the partial answer to my riddle is...a pound of feathers is heavier. Anyone know why?

<font color=red>JEN!</font color=red>

[JenDiggityDirt]

Aw come on, someone at least guess why a pound of feathers weighs more than a pound of gold...please???
And I have another one: You're in a room filled with 100% methane gas. Someone flicks their Bic. What happens?

<font color=red>JEN!</font color=red>

[Tyson]

Feathers weigh more . . .because. . .it would take sooo much more room to get to a pound of feathers.


Nothing would happen. : if a room is filled 100% of methane gas then there would be no room for a person. http://www.race-dezert.com/wwwthreads/images/icons/wink.gif



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[Tom]

A pound of Gold is not the same (16 oz) as a traditional pound, it is less. Kind of like an imperial liter is not the same as a liter

[Waldo]

Who knows what a Fathom is??? or what about a Leauge? or Metric ton and Baker's dozen???

BRAAAAAAAAP!

[Tim]

isn't a fathon 10 feet and used in diving...

[BradM]

a metric ton is 1000kg or about 2200lbs

[Tom]

And who could forget "20,000 Leagues Under the Sea"

[fishd00d]

How far under the see in feet or fathoms would that be? :)

Go Big Or Go Home
*UBCS 4 Life*

[Tom]

Pretty damn far!

[Waldo]

A fathom is 6 feet. I don't know how much/many a league is.

BRAAAAAAAAP!

[partybarge_pilot]

20,000 leagues=316,799,970.550275 FT. or 52,799,995.091712 fathoms.

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[AllwaysRcn]

A fathom is 6 feet
A league is 3 miles (nautical)
A metric ton is 1.1 tons?

Am I close?

[Tyson]

and a bakers dozen is 13.

No, I'm not gay.

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[JenDiggityDirt]

Ok, thanks for making an attempt...the reason a pound of feathers weighs more is because feathers are weighed using the Avoirdupois system, whereas gold is weighed using the Troy system. A pound on the Avoirdupois scale is greater than a Troy pound! Hehehehe what fun! And Tyson I guess your answer to the 2nd question would be right (see how easy that was for me to admit!) although I was looking for something more along the lines of there being no explosion because there would be no oxygen if it was all methane gas, but whatever, I'm over the riddle thing anyway.

<font color=red>JEN!</font color=red>

[Tyson]

Awww Jen you weren't supposed to give the answer yet I had like 5 other smart ass answers for that 1. Oh well.

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