Something to help make your head explode

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06-03-2010, 12:00 AM
ndw76

Something to help make your head explode

I gave this problem to my students. So far none of them have been able to solve it. I can't blame them, it took me a long time to figure it out. So I thought I would share it with you all. After all, that is why we are here, to help share the madness.

If you figure it out you can pm me the answer, don't spoil it for others who are still working on it.

Here it is:

<link rel="File-List" href="file:///C:%5CDOCUME%7E1%5CNathan%5CLOCALS%7E1%5CTemp%5Cmso html1%5C01%5Cclip_filelist.xml"><style>  </style> Three people have lunch together.<o></o>
The bill is $25.<o></o>
They each pay $10.<o></o>
From $30 they get $5 change.<o></o>
They give a $2 tip to the waiter<o>.</o>
That leaves $3.<o></o>
They give $1 back to each person.<o></o>
Each person has paid $9.<o></o>
$9 multiplied by 3 = $27<o>.</o>
Plus the $2 tip = $29.<o></o>
Where did the extra $1 go?<o></o>
06-03-2010, 12:37 AM
hoglahoo

There is no extra dollar

But I won't spoil the figuring :)
06-03-2010, 12:39 AM
Jimbo

Oh, there's an extra dollar all right!! That bastard waiter stole it!!!

James.
06-03-2010, 12:41 AM
Jimbo

See, this is why I think double entry book keeping should still be taught in schools.

:)

James.
06-03-2010, 12:41 AM
JimmyHAD

I was thinking sales tax but wouldn't want to give it away. What I want to know is Who's on first ? :banghead:

Edit; Thanks Lee, I just got it.
06-03-2010, 12:48 AM
kevint

Quote:

Originally Posted by Jimbo

Oh, there's an extra dollar all right!! That bastard waiter stole it!!!

James.

a 2 buck tip on a 25 dollar tab. it should be expected
06-03-2010, 01:10 AM
ndw76

Quote:

Originally Posted by kevint

a 2 buck tip on a 25 dollar tab. it should be expected

Well I am an Australian. We don't tip.
06-03-2010, 01:14 AM
kevint

Quote:

Originally Posted by ndw76

Well I am an Australian. We don't tip.

Is that a hint:D
06-03-2010, 01:33 AM
JimmyHAD

Quote:

Originally Posted by ndw76

Well I am an Australian. We don't tip.

Sounds like Mr. Pink ..... :D if you don't get that go to youtube and watch."Reservior Dogs - Tips For The Tippers". I can't post that on SRP or I'd get banned. :)
06-03-2010, 01:50 AM
ndw76

If you can't post a link to that clip I will wait until I get home to look it up. Might not be a good idea to watch it at school.
06-03-2010, 01:51 AM
ndw76

Quote:

Originally Posted by kevint

Is that a hint:D

No, that is not a hint. When I try to give hints I tend to just confuse people.
06-03-2010, 01:52 AM
JimmyHAD

Quote:

Originally Posted by ndw76

If you can't post a link to that clip I will wait until I get home to look it up. Might not be a good idea to watch it at school.

Not if you want to keep your job. :eek:
06-03-2010, 02:31 AM
onimaru55

Quote:

Originally Posted by ndw76

Well I am an Australian. We don't tip.

Sounds like some cheapskate didn't put in for the tip :p
06-03-2010, 03:43 AM
holli4pirating

Ah, I get it. Yup, no extra dollar. That did take a few minutes...
06-03-2010, 05:36 AM
ndw76

I can't believe everyone figured it out so fast. This took me about six weeks to figure out. The other teachers I work with haven't figured it out either.

I hope that doesn't say something about English teachers.
06-03-2010, 07:13 AM
onimaru55

Two of my best friends are maths teachers. It's handy as I failed maths at school :p
06-03-2010, 08:04 AM
Stubear

There is no extra dollar. What you do is take 9+9+9=27, then subtract the $2 tip, not add it on. That gives the original $25 that was paid.

So each person paid $9 (once they got their $1 change back), and the waiter got $2, which is why you take off the $2, not add it back in.

But frankly that sounds like the sort of accounting that the governments of the world are going to be using to pay off the deficits they've run up..! :D

"Hey, look George, I can make money disappear! Our deficit will be gone by July!"

:rofl2:

Thanks for sharing that one!
06-03-2010, 02:07 PM
Troggie

Stu.. you problem killer ( hopefully no one reads the whole thread before trying to figure it out ) but you are right it does seem that is how not just governments but big business run their books now days and probably one reason the world is in an economic panic right now.

I remember doing this ( or something very similar) in a problem solving class I had in High school many moons ago. My calculus teacher laughed at every wrong answer and so did the rest of the class once they knew the correct one.
06-03-2010, 02:18 PM
Stubear

Quote:

Originally Posted by Troggie

Stu.. you problem killer ( hopefully no one reads the whole thread before trying to figure it out ) but you are right it does seem that is how not just governments but big business run their books now days and probably one reason the world is in an economic panic right now.

Hehe! Hey, I'm an accountant, I do this sort of thing for a living..! You'd be amazed at some of the numbers that come across my desk lol..! :rofl2:
06-03-2010, 02:44 PM
BingoBango

I hope you teach 7th graders. I think I first saw this puzzle back then.
06-03-2010, 03:25 PM
holli4pirating

Quote:

Originally Posted by Stubear

There is no extra dollar. What you do is take 9+9+9=27, then subtract the $2 tip, not add it on. That gives the original $25 that was paid.

So each person paid $9 (once they got their $1 change back), and the waiter got $2, which is why you take off the $2, not add it back in.

Since Stu already threw this out, I figured I'd comment that I saw it a different way. I thought of the entire bill as $27 because I included the tip in the cost of the meal. Must be cause I usually pay with my debit card, so I'm used to adding the tip to the subtotal.
06-03-2010, 07:19 PM
HNSB

I think the more important question here is did they all eat the same amount of food? If not, was the distribution of their bill equitable in relation to their incomes?

Then, I'm reminded of Mystery Men: "All I'm saying is, when we split the cheque three ways the steak eater picks the pocket of the salad man."
06-03-2010, 11:56 PM
thebigspendur

Just to throw something else out.

After you bright boys have figured this go to the shaving brainbuster and answer the last question. As a matter of fact answer them all and you might be the proud owner of....
06-04-2010, 04:34 AM
gugi

Quote:

Originally Posted by ndw76

I can't believe everyone figured it out so fast. This took me about six weeks to figure out. The other teachers I work with haven't figured it out either.

I hope that doesn't say something about English teachers.

Nah, it's the DNA's fault. You're wired to believe everything at first and only then discount it. So it's often quite easy to be mislead by a wrong statement.