Math Is Fun Forum

quinton28

Member

Registered: 2007-03-04

Posts: 2

Where did the dollar go puzzel? or How come I am $2 up?

If 3 men have $10 each and buy a $25 meal and the waiter can't split the $5 change so pockets $2 and gives the diners back$1 each this means the diners have spent $27 in total. The meal costs $25 and the waiter has $2.

Facts, the diners had $10 each, they now have $1, they have spent $9 each 3 x 9 = 27. But 3x9=27 and +3 +2=32? Now there are $2 from nowhere as the restraunt has $25.

So at the end of the meal,

The restraunt has $25.

The diners have $3

The waiter has $2

This adds up to $30

However I am certain that if I received $1 change from $10 I would assume that I had spent $9.

So 3x9=27+3=30+2=32 as the restraunt has $25, the diner have spent $9 each and the waiter has $2.

This is a tricky one, and i am sure it will keep my friends and family occupied for ages.

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Where did the dollar go puzzel? or How come I am $2 up?

Where’s the problem? I don’t see any problem there.

Before the meal, the men have $30, the restaurant/waiter has $0. After the meal, the men have $3, the restaurant/waiter has $27. They should have spent $25 but because waiter doesn’t have the change, they spend $27 – $2 more – instead. $25 goes to the restaurant for the meal and the waiter keeps $2 for himself.

So what’s the problem?

Last edited by JaneFairfax (2007-03-04 14:09:47)

pi man

Member

Registered: 2006-07-06

Posts: 251

Re: Where did the dollar go puzzel? or How come I am $2 up?

That's a classic puzzle.   It's usually written something like below:

Three ladies go to a restaurant for a meal. They receive a bill for $30. They each put $10 on the table, which the waiter collects and takes to the till. The cashier informs the waiter that the bill should only have been for $25 and returns $5 to the waiter in $1 coins. On the way back to the table the waiter realizes that he cannot divide the coins equally between the ladies. As they didn’t know the total of the revised bill, he decides to put $2 in his own pocket and give each of the ladies $1.

Now that each lady has been given a dollar back, each of the ladies has paid $9. Three times 9 is 27. The waiter has $2 in his pocket. Two plus 27 is $29. The ladies originally handed over $30. Where is the missing dollar?

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Where did the dollar go puzzel? or How come I am $2 up?

Now that each lady has been given a dollar back, each of the ladies has paid $9. Three times 9 is 27. The waiter has $2 in his pocket. Two plus 27 is $29. The ladies originally handed over $30. Where is the missing dollar?

Now you’re confusing me even more. Why do you plus 2 to the 27? The $27 includes the $2 that the waiter deviously pockets for himself, so what for add 2 to it?

See,

            $27                          =      $25            +          $2
(amount spent by the ladies)    (price of meal)     (unreturned change)

Please explain to me why you need to add 2 to 27 because this is getting on my nerves.

Last edited by JaneFairfax (2007-03-05 03:03:30)

Maelwys

Member

Registered: 2007-02-02

Posts: 161

Re: Where did the dollar go puzzel? or How come I am $2 up?

Now you’re confusing me even more. Why do you plus 2 to the 27? The $27 includes the $2 that the waiter deviously pockets for himself, so what for add 2 to it?

See,

            $27                          =      $25            +          $2
(amount spent by the ladies)    (price of meal)     (unreturned change)

Please explain to me why you need to add 2 to 27 because this is getting on my nerves.

And that's exactly the point of the riddle. By phrasing it the way that Pi did (as the riddle does), it tricks the listener into thinking that there's money missing. But as you picked up on, there isn't any money missing at all, because applying the numbers in that way is false logic. But if you don't realize that right away, it can be a tricky puzzle, trying to figure out where the "missing dollar" went.

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Where did the dollar go puzzel? or How come I am $2 up?

Ah. So it’s not a puzzle at all. It’s just doing arithmetic in illogical ways.

lightning

Real Member

Registered: 2007-02-26

Posts: 2,060

Re: Where did the dollar go puzzel? or How come I am $2 up?

i got one i have $1 i lost $2 where did the pound come from

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mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Where did the dollar go puzzel? or How come I am $2 up?

I don't know where it came from, but this is the guy who received it:

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Why did the vector cross the road?
It wanted to be normal.

lightning

Real Member

Registered: 2007-02-26

Posts: 2,060

Re: Where did the dollar go puzzel? or How come I am $2 up?

his dad told him to put it in the bank but he lost two pounds

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