Three tourists go to Transylvania to visit Dracula’s castle. They arrive there at night and decide to spend the night at a local inn. There’s a sign at the entrance reading: “bed & breakfast - $10”. The innkeeper’s little boy calls his father, and the tourists hand him $30 ($10 from each): “We’d like three rooms, please.” But the innkeeper says: “I’m sorry, this period of the year the inn is quite crowded. There’s only a there-bed room left. If you will stay in it I’ll charge you only $25.” The tourists accept and the innkeeper hands them back five $1 dollar bills. The tourists decide that each of them take a $1 dollar bill and the two dollars left be given to the innkeeper’s little boy, who has helped them carry their luggage to their room. “Wait a minute,” says one of the tourists to the other two. “I think we’ve been cheated.” “What do you mean?” “I mean, each of us gave the innkeeper $10? And received $1 dollars back, right? We actually paid the innkeeper $9 dollars each, because ten minus one equals nine.” “So, what’s wrong with that?” “Well, one dollar is missing, because nine dollars times three is twenty-seven, plus two dollars given to the little boy, twenty-nine! Where is the missing dollar?”
Clever!
Here’s how I would answer it:
The one guy said “we actually paid the innkeeper nine dollars each,” however I don’t think that’s true. They each paid nine dollars to this general fund which was paid out to both the innkeeper and to his son - 25 of the 27 to the inkeeper, 2 of the 27 to the boy. Meanwhile, each of them got to keep a dollar - hence the three dollars they have in hand plus the 27 they paid to the innkeeper and his boy equals 30 bucks and no cheating has occured.
The trick in the question happens when the fellow says “twenty seven plus the two given the little boy equals 29 dollars.” The problem with that statement is that the two given the little boy is already included in the 27 the three paid in all. Hence, the two given to the little boy shouldn’t be added to the 27 but rather subtracted to get 25 - the amount they paid for the room.
-Kris
:smack:
I checked the links out.
As for why this little problem is a recurrent one, I say we should all go to Transylvania and ask the old vampire.
;j
Consider the following.
2 x 3 = 6
2 + 3 = 5
Where did the missing one go?
While the traditional riddle is more complicated then the above, mathematically it’s no more sensible. Just because you add, subtract, and multiply some numbers, there’s no reason you should get identical results from different equations. 29 not equalling 30 is no more significant than 5 not equalling 6.
5 doesn’t equal 6?
Damn my parents for not looking into school vouchers!
I think it does, for very large values of 5.
… and suitably small values of 6.