The currency of the room ...

Three young people take a dish on a sunny terrace in the month of June They have to pay 30 euros and give each a room of 10 euros. The owner, charming , makes them a discount of 5 euros. The server then takes 5 1 coins , unable to share the three he decided to slip surreptitiously 2 euros in his pocket and generously gives 1 coin to each of the three young men .

 

 
Finally each paid ( 10 - 1 ) euros, so 9 euros. By adding 2 euros of Sir, we obtain ( (9 x 3) + 2) euros or 29 euros. BUT we had 30 euros. What happened to the last euro?
 

 

 

Solutions : 

 

 

 

This is good scam , but it is in the text : it makes no sense to calculate 27 + 2 .
Either one calculates from 27 :
9 x 3 = 27 ( 27 euros disbursed , 25 flat and 2 in the indelicate pocket )
and then calculates 27-2 to find the 25 euros due;
Either one calculates from 30 :
30 = 25 + 2 + 3 ( flat more money : 2 euros in the pocket and made ​​3 euros )
or 30 = 27 + 3 (27 euros and 3 euros paid actually rendered .

I await you commentaire :D ! (Enjoy)