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Main => Everything Else => Topic started by: shardian on June 25, 2007, 01:33:35 pm

Title: A riddle for you guys.
Post by: shardian on June 25, 2007, 01:33:35 pm
This was asked at lunch today:

Three guys are on a road trip and stop at a Hotel for the night. The room costs $30, so each guy puts in $10. After paying, the owner realizes the men overpaid, so he gives them $5 back, two of which they give to the bell hop for carrying up the luggage. After each receiving their dollar back, they each paid $9, and the bell hop kept $2. So, $9 x 3 + $2 = $29. Where did the other dollar go?
Title: Re: A riddle for you guys.
Post by: Zero_Hour on June 25, 2007, 01:40:51 pm
I haven't heard that one in a long time. Much easier to figure it out when I see it written down, but I won't spoil it.  ;)
Title: Re: A riddle for you guys.
Post by: Chris G on June 25, 2007, 01:45:21 pm
The $2 is already counted in the $27.  It should be $27 spent plus $3 kept.
Title: Re: A riddle for you guys.
Post by: shardian on June 25, 2007, 01:50:03 pm
I haven't heard that one in a long time. Much easier to figure it out when I see it written down, but I won't spoil it.  ;)

hehe, I kept zoning out before the guy could finish telling it to me. ;D
Title: Re: A riddle for you guys.
Post by: ChadTower on June 25, 2007, 01:51:05 pm

Seriously, solving someone's mistake in a math word problem... you should have zoned him out.
Title: Re: A riddle for you guys.
Post by: shardian on June 25, 2007, 01:56:45 pm
I missed the majority of the debate as I went out to lunch, but the guys that were in the lunch room debated it the whole hour. Even to the point that they tore up some paper to act out the riddle. If you act it out though exactly as the riddle is spoken, it makes a very compelling case that something is weird about it. Hell, I confused myself even trying to explain the answer to the other guys.
Title: Re: A riddle for you guys.
Post by: boykster on June 25, 2007, 03:00:21 pm
shouldn't the room cost $25 for the initial math to even make sense?

Title: Re: A riddle for you guys.
Post by: shardian on June 25, 2007, 03:02:52 pm
shouldn't the room cost $25 for the initial math to even make sense?



It does cost $25.
Title: Re: A riddle for you guys.
Post by: boykster on June 25, 2007, 03:09:26 pm
written that way for misdirection then.....

the solution of 3 x $9  + $2 is deceptive, the actual solution should be 3 x $9 + $3 (their change) as the $2 is included in the 3 x $9 figure
Title: Re: A riddle for you guys.
Post by: shardian on June 25, 2007, 03:40:18 pm
I did the math for a few of the guys up here and they are still cornfused about it. They keep getting stuck on the "27+2" = 29 part of the riddle.
Title: Re: A riddle for you guys.
Post by: Apollo on June 25, 2007, 05:00:35 pm
I've never seen this but is the misdirection that they actually paid $8.33333 each for the room not $9?

so 3 * 8.33333 = $25 plus the $2 for the hop and their $1 each = $30?
Title: Re: A riddle for you guys.
Post by: _) (V) (-) on June 26, 2007, 08:15:42 am
Quote
Where did the other dollar go?

Into the change machine for tokens of course.
Duh!  ;)
Title: Re: A riddle for you guys.
Post by: cdbrown on June 26, 2007, 08:26:40 am
Easy way to explain is they each paid $9 - that went towards the $2 for the tip and the rest for the room.
Title: Re: A riddle for you guys.
Post by: More Cowbell on June 26, 2007, 12:05:11 pm
Yeah, the misdirection is in the $27+$2 to get to $30. You're really trying to get to $25 which is the new price of the room. So $9x3=$27 minus $2 for tip = $25.
Title: Re: A riddle for you guys.
Post by: Spaz Monkey on June 28, 2007, 12:29:51 am
Original room cost $30 = 3 guys @ $10ea
New room cost $25 = 3 guys @ $8.33333 ea plus $1 refund for each guy ($3) and $2 tip.
I'll use _ as the "repeat untill infinity" mark here.
You can't divide 1 by 3.  Look up on wikipedia "0.999...".  You'll see an entry that talks about why 0.33_ *3 = 1.0
Title: Re: A riddle for you guys.
Post by: boykster on June 28, 2007, 12:36:30 am
Its not that complicated...

The cost of the room is $25

The tip is $2

The change is $3 -> $1 each.

3* $9 + $2 is deceptive because the 3*$9 INCLUDES the $2 tip ($25 + $2 = $27), and the change is $3

Classic misdirection......
Title: Re: A riddle for you guys.
Post by: jbox on June 28, 2007, 02:23:59 am
No it's not.
(http://www.heathersanimations.com/Silly/maus_elefant.gif)
Title: Re: A riddle for you guys.
Post by: FrizzleFried on June 28, 2007, 10:27:56 am
Yes it is...and I head this when I was in 4th grade....which MAKES IT CLASSIC.
Title: Re: A riddle for you guys.
Post by: More Cowbell on June 28, 2007, 10:31:05 am
It's classic misdirecti... look a shiny squirrel!