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Three men go to a restaurant. They order some food. After they have finished, they ask for the bill. The bill was 30$ . They pay the bill and leave the restaurant.

As soon as they leave, the manager find out that there was a miscalculation and that they actually had to pay 25$ .

He calls the waiter, give him the extra 5\$, and ask him to pass this money back to men. The waiter leaves the restaurant with 5\$ , but he put 2\$ in his pocket and give each man 1\$.

So

Each man payed $ 10\$-1\$ = 9\$ $.
Three man payed $ 9\$*3=27\$ $.
The waiter has $ 2\$ $
The total is $ 27\$ + 2\$ = 29\$ $

Where is the last $ 1\$ $?

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  • $\begingroup$ Please solve this: I am new in this site... I knew a puzzle, I've searched the site to find if the puzzle is there or not.. I couldn't find it, (as you might guess a puzzle can be asked in many different ways) . I put a new post... I get 4 down votes. Why do I get down votes ? Isn't a marked as duplicate enough ?! $\endgroup$
    – Alireza Fattahi
    Commented Aug 30, 2016 at 5:28

3 Answers 3

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Let's represent restaurant manager by R, men by M and waiter by W.

Since money can neither be created nor be destroyed (unless government is involved).

We can represent it by a simple mathematical equation :

Money(R) + Money(M) + Money(W) = 0

For manager,

Money(R) = 30\$ - 5\$ = 25\$

For mens,

Money(M) = -30\$ + 3\$ = -27$

For waiter,

Money(W) = 2\$

summing them up

25 - 27 + 2 = 0.

And explanation to why your calculation was wrong:

27 should be represented with a negative sign, since that was a loss (from calculation perspective). And the 2 should be positive as it was gain.

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    $\begingroup$ ...It's a restaurant. :P $\endgroup$
    – Mithical
    Commented Aug 29, 2016 at 12:57
  • $\begingroup$ @Mithrandir Done..:D $\endgroup$
    – Laschet Jain
    Commented Aug 29, 2016 at 13:00
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    $\begingroup$ Haha, law of conservation of money ^-^ $\endgroup$
    – ABcDexter
    Commented Aug 29, 2016 at 17:21
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    $\begingroup$ @ABcDexter I know :D.. while writing the answer this struck me. $\endgroup$
    – Laschet Jain
    Commented Aug 29, 2016 at 17:26
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In fact, they payed 27$, 25$ to the restaurant and 2$ to the waiter.

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This is a classic puzzle. The answer is

They gave \$30. The waiter keeps 2 and gives 3 back. Everyone gets one dollar. \$25 + \$2 + \$3 = \$30. No missing money.

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