WTF Math?

Discussion in 'General Off-Topic Chat' started by amrboghdady, Aug 15, 2011.

  1. amrboghdady

    amrboghdady Member

    Sep 4, 2010
    United States
    Ok, here is the equation, tell me why it does not work?

    3 guys go to a Hotel to rent a room.

    Clerk says its 30 bucks.

    Each guy gives the clerk 10 bucks [ 10x3=30 ]

    They go to room.

    Clerk finds his mistake and calls bellboy over.

    Tells bellboy, I overcharged these guys 5 dollars. Room is only 25 dollars. Take this 5 dollars to them.

    Ok, says bellboy and goes to guys room.

    After they answer door he explains they were over charged 5 dollars. [ 25 + 5 =30 ]

    Ok, say the guys, give us each back one dollar, and keep 2 for a tip to make it work out. [ 1+1+1+2=5 ]

    Bellboy does that and leaves with his 2 dollar tip.

    WTF math is happening. 25 + 5 =30 right? right.

    OK, now the 3 guys starting out paying 10 dollars each. They now each get back one dollar. [ 10 -1 = 9 ]

    Now they have only paid 9 dollars each and the bellboy got a 2 dollar tip.

    3 x 9 =27 plus the 2 the bellboy got = 29 dollars. WTF ? They started out with paying 30 dollars.

    If the math works one way, then why not the other? Imagine if this is a business transaction and the numbers are millions. Who gets the missing dollar?
  2. Narayan

    Narayan desu~

    Sep 29, 2010
    edit: wait, that doesn't work...

    okay, 2 paid $8 and one paid $9 = $25
    and the 5 dollars.

    edit: haha think you can fool me with saying each one paid $9, and adding the $2. if that's the case, you need to add the $3 too, then it would be $32.
  3. prowler

    prowler Sony

    Jul 14, 2009
    You lost me at equation.
  4. Nathan Drake

    Nathan Drake Obligations fulfilled, now I depart.

    Jan 2, 2011
    They each pay $10.

    10 10 10

    5 is taken. That is about $1.67 taken off per person. So that's about $8.33 paid per person.

    8.33 8.33 8.33

    That totals $25. They are then given $1 back each, and $2 is given to the bellhop.

    8.33 + 8.33 + 8.33 + 1 + 1 + 1 +2 = 30

    The problem was that when looked at collectively, the numbers are a little harder to see. Regardless, businesses are handled carefully and with far more than basic math skills.
  5. Zarcon

    Zarcon .:~Enigmatic Wanderer~:.

    Former Staff
    Nov 6, 2002
    Toronto, Ontario
  6. amrboghdady

    amrboghdady Member

    Sep 4, 2010
    United States
    Haha, its really much simpler than that
    It took me a good while to figure it out, just to discover how easy it is

    They each paid $9, which sums to $27, that $27 already includes the $2 tips, so you need not add it again [​IMG]

    Hope I made it clear enough, cause all these numbers make it so complicated xD
  7. Shinigami357

    Shinigami357 Current "give a fuck" level: Honey Badger

    Jul 29, 2010
    Without having to resort to decimals and stuff [change? what's that? LOL], I think this question, and many more like it, are deliberately made just to make this conundrum.

    I think the thing that really makes questions like this is, as far as I remember, the number subtracted from the original tally is always prime. 5 is a prime number. We are then forced to divide it as equally as possible, but without resorting to decimals, in which case [because prime numbers cannot be divided by anything other than 1 and the number itself] we are left with a surplus on one side and a deficit on another. And thus, the whole thing evolve into a clusterf*ck [even if you mash B. LOL]

    That's my take on it.
  8. Snailface

    Snailface My frothing demand for 3ds homebrew is increasing

    Sep 20, 2010
    Engine Room with Cyan, watching him learn.
    Here's a graph for the visual thinkers [​IMG] :
    The confusion* comes from the way it's explained. If you follow the numbers, things make sense.

    *This is what change artists prey on. [​IMG]
  9. Chikaku-chan

    Chikaku-chan ᏁᎽᎪ~

    Aug 9, 2011
    New Zealand
    You lost me at "Ok,"
  10. pistone

    pistone GBAtemp Advanced Fan

    Feb 18, 2010
    in your heart...coz secretly you love me !!!!
    this ^ ,or you can 5/3 and it comes out 1.66666666....7
    this 0.00000000....7 is the guilty as the number without this 0.0000000...7 cant become a full one (i dont know hot to write it in English hope its ok )
    for example 1 and say at 0.944444444444444444...3
  11. r3gR3t

    r3gR3t GBAtemp Regular

    Dec 7, 2010
    United States
    The pits of Hell
    Ha, this brings back old memories [​IMG]
    The first time I saw this riddle was when I first played MMBN4 Red Sun and installed the 'Humor' program on MegaMan [​IMG]

    Anyways, I second what Shinigami357 said [​IMG]
  12. SinHarvest24

    SinHarvest24 Shiroyasha

    Oct 8, 2010
    Anywhere you think of me.

    Pretty nice teaser you got here but you'll need to up your game up for the temp. [​IMG]
  13. The_Dragons_Mast

    The_Dragons_Mast GBAtemp Advanced Fan

    Apr 20, 2007
    I cant really see how this is hard:P.
    1 guy payed a dollar more to the hotel than the other 2 while the other 2 each payed a dollar to the bellboy.
    What exactly doesn't make sense???
  14. chris888222

    chris888222 GBAtemp's Flygon Fan

    Oct 11, 2010
    This riddle is very famous...

    And it's not really math related, but rather logic. [​IMG]
  15. WigWrm

    WigWrm GBAtemp Regular

    Apr 17, 2007
    United States
    Nathan Drake explains it the best. Each person paid 1/3 of the bill. They got the 5 bucks back. They gave 2 to the bell boy. 25/3=8.333 repeating. Take the decimal from that number and multiply it by 3. There's your lost dollar.
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