Where Is the Missing Dollar in the Room Rental Puzzle?

[mineys]

So there are three guys fresh out of college who want to save money, so they decide to rent a room. The room costs 30 dollars, so they split it 10-10-10. They pay, but it turns out the room is only $25, so the manager asks the bellboy to take $5 and to give it back. The bellboy takes a 'tip' off the top, and gives back $3. So, the paid $9 each. 9*3=27. The bellboy has $2. 9*3+2=$29. Where is the last dollar?

If you know the answer or have heard it before, a simple "oooh, i get it" will suffice. Please do not spoil it for others until they are just about ready to commit suicide.

That is all.

 

[cristo]

Highlight to read: Why have you done 9*3+2=29? 9*3=27, the total amount paid (25 for the room, 2 to the bellboy), then each person gets one dollar back each, so this sums to 30.

Note, we have a https://www.physicsforums.com/forumdisplay.php?f=33 forum.

 

[Gib Z]

Yea I've seen this one before.

 

[mark-ashleigh]

Ohhh i get it...lol

 

[uart]

You probably won't catch too many people around here with that one. :D

 

[murshid_islam]

i have heard it before. its a very widely known brain teaser.

 

[complexPHILOSOPHY]

I think this is more of a tautology and not a maths problem.

The original total cost of the room = $30.00.
Upon review, the total cost of the room is now = $25.00.

This leaves $5.00.

If they bell man takes $2.00, there are $3.00 remaining.

25.00+2.00 = 27 + 3 = 30.

Unless I am an idiot, I don't see the dilemma. I am going to go find the solution to this and see if there is a trick or something -- it seems to straight forward to me (I have never seen this before).

EDIT: can't seem to find this problem when I google it -- did you rewrite it?

 

[cristo]

Well, I'd never heard it before, but the "solution" is clear! Just like any other brain teaser, it's meant to catch you out and disguise the answer. However, as uart says, I don't think many mathematicians will be caught out by it!