Thread: Post A Logic Puzzle

Three men in a cafe order a meal the total cost of which is $15. They each contribute $5. The waiter takes the money to the chef who recognizes the three as friends and asks the waiter to return $5 to the men.

The waiter is short on cash so instead of going to the trouble of splitting the $5 between the three he simply gives them $1 each and pockets the remaining $2 for himself.

Now, each of the men effectively paid $4, the total paid is therefore $12. Add the $2 in the waiters pocket and this comes to $14.....where has the other $1 gone from the original $15?

What if each of the men refused the dollar refund from the chef so they effectivly paid $4 each, the total paid is therefore $12 and the waiter then keeps the $3 + $2 in already in his pocket for a total of $17 of the original $15.


Here is one.
You're on a game show and the grand prize is a trip for two with your Fav DV member [trip desination your choice] and is behind one door of three doors. The other 2 doors are only lousy DV T-shirts .

The gameshow host asks you to select a door

Door 1 Door 2 Door 3

You pick door #1( 1,2,3 does't matter it stays closed). The host then opens one of the other two remaining doors to reveal one styling DV T-shirt. He now procedes to ask you, Would you like to change the door that you picked? (obviously you want to get the trip with a choice DV member, not the T-shirt so now question time...)

Do you switch doors or not, please provide the reasoning for your answer.
And yes, there is a correct answer.

BTW I hate this one......

Originally Posted by Squall

The last topic got deleted because of the server problem.

Resume!
[/b]

Damn weird forum data loss! I actually posted a topic, but then it got delted, and after I got a bunch of replies too , and I guess this one took its topic number because when I click on the view the reply to your topic thing, it takes me to this topic. Kinda weird as hell, but being as I am here, I might as well post a riddle:

It is the GRY riddle, kinda tricky, but solvable-

Think of words ending in -GRY. Angry and hungry are two of them. There are only three words in the English language. What is the third word? The word is something that everyone uses every day. If you have listened carefully, I have already told you what it is.

the english language

Language. I'd say.

Originally Posted by Meidi

Language. I'd say.
[/b]

Yep. Did you know it before, or are you just damned good at riddles? I spent like ten minutes on this riddle, and ended up giving up to look for the answer.

Here's another one: What weighs more, a pound of feathers or a pound of gold?

If A man walks in to a bar.... What is the nature of the unverse?

Originally Posted by PenguinLord13

Yep. Did you know it before, or are you just damned good at riddles? I spent like ten minutes on this riddle, and ended up giving up to look for the answer.

Here's another one: What weighs more, a pound of feathers or a pound of gold?
[/b]

Wait I don't get it? How's language end in GRY?

They weigh the same.

Originally Posted by Squall

Wait I don't get it? How's language end in GRY?

They weigh the same.
[/b]

gry doesn't have anything to do with it. there are only three words in "the english language" ... the first two are the english and the third is language.

nobody's gotten mine yet.

Originally Posted by Squall

They weigh the same.
[/b]

False, it's the feathers. It is a riddle I saw a while ago. For some reason gold (and other precious metals/stones) is measured in troy ounces instead of regular ounces, and though a troy ounce is more than a regular ounce, there are only 12 troy ounces in a troy pound, so a troy pound weighs less than a regular pound, and therefore the feathers weigh more. Don't ask me why this is though, it is just another f**cked up measuring system created by the british and used by americans.

Originally Posted by jacobo

Three men in a cafe order a meal the total cost of which is $15. They each contribute $5. The waiter takes the money to the chef who recognizes the three as friends and asks the waiter to return $5 to the men.

The waiter is short on cash so instead of going to the trouble of splitting the $5 between the three he simply gives them $1 each and pockets the remaining $2 for himself.

Now, each of the men effectively paid $4, the total paid is therefore $12. Add the $2 in the waiters pocket and this comes to $14.....where has the other $1 gone from the original $15?
[/b]

it's all down to percentages

In the actual scenario, the men get a 1/3 off of the meal ($15 reduced to $10, or 66.66%)
but the waiter defrauds them of 13.33% of the total

it all goes wrong (but is excellently disguised with clever wording) when you say "Now, each of the men effectively paid $4"

You're altering the distribution of the values but not altering the percentages

to make it work,
the men pay (3 x $4) = $12
each man has $1.00 left in his pocket
Chef gives 1/3 off of price (meal costs $8. men should get $4 back) - that's $4 between 3, so $1.33 each
but the waiter defrauds them of 13.33% of the total (waiter pockets $1.60)
Men actually get back $2.40 between them ($0.80 each)

(3 x 0.8) + (3 x 1) + 1.6 + 8 = 15

Jesus, I dwelled over that riddle for ages and couldn't get it.

I think I've fuxored it up, tho

cause in the "effectively" second scenario the men shouldn't get any money back at all
(I don't think)

crap

Originally Posted by Ynot

I think I've fuxored it up, tho

cause in the "effectively" second scenario the men shouldn't get any money back at all
(I don't think)

crap
[/b]

You shouldn't have said that. I believed it - I couldn't be bothered to check for myself. I just saw lots of maths and my mind imploded.

I can visualise the error
but can't quite put my finger on it when it's on paper

it's all in the "each of the men effectively paid $4" bit
cause while at the end of the day, they have
you can't just add (3 x 4) + 2 together
it's wrong

They DID pay $5 each - this 3x5 is in a set of brackets at the beginning of the equation
they just happened to get $1 each back (this is equated in a seperate set of brackets)

I don't think you can simply subtract $1 from each of their contributions like that
it mucks up the brackets


oh for god sake
JACOBO
ANSWER

I'm dying here

Dun Dun Dun!

I have a way to make your brains un-implode.

Guys give cook $15. Cook is nice and give them thier money back. They have now effectively paid $0 each! Where did the $15 go?

They have it. You need to add the amount the guys have (3), the cook has (10) and that the waiter has (2).

hokay so here's how i figured it out...

there are five people in this equation... the chef, the waiter and the three friends (friends 1, friend 2, and friend 3)

break down who has what...

the chef has 10 dollars because he sent 5 back...

the waiter has 2 because he only kept 2...

and the friends have 3...

that's fifteen.

the guy named after the sandwich place got it.

hokay next

Three men in a cafe order a meal the total cost of which is $15. They each contribute $5. The waiter takes the money to the chef who recognizes the three as friends and asks the waiter to return $5 to the men.

The waiter is short on cash so instead of going to the trouble of splitting the $5 between the three he simply gives them $1 each and pockets the remaining $2 for himself.

Now, each of the men effectively paid $4, the total paid is therefore $12. Add the $2 in the waiters pocket and this comes to $14.....where has the other $1 gone from the original $15?[/b]

$15 floats about.

Chef keeps $10.
Group gets $3.
Waiter pockets $2.

Total = $15.

What's the big deal?

That said, the problem is very cleverly put together. If you think by the logic the problem provides, you'll never get the answer. Taking the raw facts instead (I think Ynot was close to it here, although his method was by all means hyperbolic), you know that the chef has $10, the waiter pockets $2 and the group gets back $3 - nothing's gone missing. It's with the "they all paid $4" that you start to change things.

If you think about it, this is a bit like 1/3 + 2/3 = 1. It's easy to slip by.

Do you switch doors or not, please provide the reasoning for your answer.
And yes, there is a correct answer.[/b]

You switch doors. (Monty Hall problem).

The probability of picking the right door is 1/3 first time around, when there are three possibilities.
When a wrong door is eliminated, the probability of picking the right door is a 1/2. Therefore, switch.

Think of words ending in -GRY. Angry and hungry are two of them. There are only three words in the English language. What is the third word? The word is something that everyone uses every day. If you have listened carefully, I have already told you what it is.[/b]

Three. Maybe.

So here's a problem I like:

You're in Hell. During your stay in Hell, you get $5 every day, but you have to pay $1 to the Devil to pay for the heating. After all the days on Earth have passed (i.e. an infinite amount of days), you get to take your money and go.

Unfortunately, you don't get to handle the money yourself and you need to choose from two bankers to do it all for you:

• Monty. Monty puts the $5 into a sack, takes a dollar out and gives it to the Devil.
• Marilyn. Marilyn gives $1 to the Devil and puts the remaining $4 into the sack.

Who do you choose to bank for you and why?

Originally Posted by Kaniaz

So here's a problem I like:

You're in Hell. During your stay in Hell, you get $5 every day, but you have to pay $1 to the Devil to pay for the heating. After all the days on Earth have passed (i.e. an infinite amount of days), you get to take your money and go.

Unfortunately, you don't get to handle the money yourself and you need to choose from two bankers to do it all for you:

• Monty. Monty puts the $5 into a sack, takes a dollar out and gives it to the Devil.
• Marilyn. Marilyn gives $1 to the Devil and puts the remaining $4 into the sack.

Who do you choose to bank for you and why?
[/b]

you never get your money because, according to this riddle, the days on earth are never-ending... therefore your stay in hell is never-ending.

you never get your money because, according to this riddle, the days on earth are never-ending... therefore your stay in hell is never-ending.[/b]

Wrong. You do get your money (it just takes a long time).

Marilyn: I like girls

are you there when they are doing it?

No. If you were or not is completely irrelevant, all the information you need is there.

Coincidentally Marilyn is the (usually) correct choice, but why?

because a) Monty is being inificent, and b) he could be taking out more then one dollar/rand

what intreges me is the fact you said usually