Another brain teaser.

[smudge]

This Q is from my husband:

Some years ago, I used to know a maths conundrum, where a builder's boy was given a pound to go to a cafe for some rolls for the blokes. The girl in the cafe offered the boy 3 for such & such, which saved such & such & left him such & such change - but when the items were added up singly, 2 bob mysteriously became unaccountable.

Does anyone remember this?

(As you can see, it was a very long time ago!).

[kev100]

This is it just set in a different location.

Three guys go to a hotel and tells the clerk they want to rent a room. The clerk says: "Fine, that'll be $30." They all take $10 each and pay the man, and go to their room. The manager of the hotel told the clerk: "You messed up man, today is Friday and it costs $25 a night, so go up to the guests and give them their $5 dollars back." The clerk takes 5 one dollar bills and goes up to the room. He tells the guys that he will give them each a dollar and keep two just as a tip. This means that each individual payed $9 each. Multiplying that by three is $27 dollars and the clerk keeping $2 makes the sum be $29 dollars. What happened to the missing dollar?

[smudge]

Thank you Kev, I shall print that off & give it to my husband tonight.

Too complicated for me this time of the day!

[WaldoMcFroog]

And the answer is that there is no missing dollar. The trick is that at one point the puzzle is counting up from $25, at another counting down from $30.

They pay $30. The clerk is supposed to return $5. So, the sum should be Hotel's money minus the men's money - $30 - $5 = $25 - which is correct.
The next part of the sum counts the return of $1 each to the men, totalling $3. $30 - $3 = $27 total payment from the men to the hotel. The other $2 is not returned to the hotel, but to the clerk. Imagine the clerk had not retained it but had returned it to the men. The correct sum would be $27 - $2 = $25 - which is correct. Instead, the puzzle adds the $2 to the $27, creating the impression a dollar has been lost.

[smudge]

Cheers Waldo - I think I'll wait 'til the end of the day, then print the whole page off, just in case someone else comes up with another one!

[Hamish]

Alternatively you could say that the statement - each individual paid 9$ is false. total paid is (30-5)/3+1 which is 9.33$. The sum done for you is incorrect.

[smudge]

Thanks Hamish - OMG it gets worse!

[smudge]

My husband says "Thank you" for your answers, he can at least sleep at night now!