WTF Math?

[amrboghdady]

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?

 

[nryn99]

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.

 

[prowler]

You lost me at equation.

 

[Nathan Drake]

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.

 

[Zarcon]

This is a pretty famous riddle.
http://en.wikipedia.org/wiki/Missing_dollar_riddle

It's more misdirection than "wtf math".

 

[amrboghdady]

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

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

 

[Shinigami357]

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.

 

[Snailface]

Here's a graph for the visual thinkers

:

The confusion* comes from the way it's explained. If you follow the numbers, things make sense.

*This is what change artists prey on.

 

[Chikaku-chan]

You lost me at "Ok,"

 

[pistone]

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.

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

 

[r3gR3t]

Ha, this brings back old memories

The first time I saw this riddle was when I first played MMBN4 Red Sun and installed the 'Humor' program on MegaMan

Anyways, I second what Shinigami357 said

 

[SinHarvest24]

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

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

This.


Pretty nice teaser you got here but you'll need to up your game up for the temp.

 

[The_Dragons_Mast]

I cant really see how this is hard.
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???

 

[chris888222]

This riddle is very famous...

And it's not really math related, but rather logic.

 

[WigWrm]

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.