# Another math problem (fun)

#### MrChips

Joined Oct 2, 2009
19,728
Three friends were in a restaurant and at the end of the meal the bill comes up to $27 including gratuities. They each give$10 to the waiter. The waiter goes to the cashier who notices that the waiter had made a mistake in tallying the tab. The correct total is $25. The cashier gives the waiter five$1 coins in change (they don't print $1 bills anymore). On the way back to the table, the waiter ponders on how he is going to split$5 three ways.
No problem, he thinks. "They think the total is $27. I will give them each$1 in change and I'll keep the remaining $2. Problem solved." Here is the math question. Each customer paid$9, times three equals $27. The waiter kept$2, equals $29. What happened to the missing$1?

(This one works best after your friends have had a few drinks.)

#### WBahn

Joined Mar 31, 2012
24,966
Each customer paid $9 totaling$27. The waiter kept $2 of the$27 dollars, leaving $25 to pay the bill. #### MaxHeadRoom Joined Jul 18, 2013 19,387 That one has been around since the 1960's to my knowledge. Max. #### strantor Joined Oct 3, 2010 5,177 This one got me good when I was a kid. I remember trying to work it out with 30 scraps of paper. Thread Starter #### MrChips Joined Oct 2, 2009 19,728 That one has been around since the 1960's to my knowledge. Max. Must be. That was when it was told to us by our math teacher. The mathematically challenged in the class couldn't figure it out no matter how hard you tried. #### strantor Joined Oct 3, 2010 5,177 Must be. That was when it was told to us by our math teacher. The mathematically challenged in the class couldn't figure it out no matter how hard you tried. Mathematically challenged? Maybe I'm just trying to give myself some consolation, but I think that problem would stump all but the brightest people on the first go-round (and probably the 2nd, 3rd) #### WBahn Joined Mar 31, 2012 24,966 Mathematically challenged? Maybe I'm just trying to give myself some consolation, but I think that problem would stump all but the brightest people on the first go-round (and probably the 2nd, 3rd) It's not so much a difficulty with math as it is letting the person that asks a question bias you with a false assumption. If the "math question" has simply been to account for the entire$30 originally given to the waiter, would anyone be stumped? No. What happens to every dollar was clearly stated. But the person that asked the question explicitly adds $2 to$27 even though there is NOTHING in the problem that indicates any justification for doing so. But by incorporating it into the question, the person asking the question leads the person being asked to defer to authority and blindly accept that performing this summation is a reasonable thing to do when accounting for the money.

My guess is that if you tested the people that are given this problem you would find that those that really struggle with it tend to be highly field dependent, because field dependence is highly correlated with deferring to authority while field independence is highly correlated with questioning authority (i.e., not accepting things at face value just because it is presented by someone whose credentials aren't suspect).

#### GopherT

Joined Nov 23, 2012
8,012
Just order an extra beer and it all comes out even.

#### shortbus

Joined Sep 30, 2009
7,219
This was going around the room at our Thanksgiving gathering.

#### WBahn

Joined Mar 31, 2012
24,966
Even though I've had plenty of experience with people whose reasoning and logic skills are at least as bad as her's purports to be, I take all of these videos with a huge grain of salt because so many of them are nothing but staged fakes. But whether it is or not, the interviewer is doing a horrible job because he just keeps asking the same question over and over and over (until the very end) when it is clear she doesn't understand the question and it is equally clear how she is interpreting it. If it isn't staged, then why should he be surprised that someone answers the same question the same way time after time, and if it is staged, it isn't a very good script because what is so noteworthy about someone giving the same wrong answer to the same question repeatedly?

#### Raymond Genovese

Joined Mar 5, 2016
1,658
Even though I've had plenty of experience with people whose reasoning and logic skills are at least as bad as her's purports to be,/---/
No argument from me as to the possibility of "staged entertainment". If it is genuine, however, I would argue that her responding has little to do with reasoning or logic skills, it has much more to do with listening deficits and comprehension bias. Those, in my view, are distinct, but not necessarily completely independent, from reasoning and logic.

She insists from the start on hearing the question, "How old were you five years ago?" and not "How old are you if you were born five years ago?" Possibly primed by previous addition/subtraction problems. She has a well designed filter at work - a predisposition. We all have those I suppose and this is just an umm, "robust" example. Not unlike the old children's riddle, "What is heavier, a pound of feathers or a pound of lead?"

In defense of the recipients of many a "Duh?".... if only they changed the question to "What feels heavier, a pound of feathers or a pound of lead?"

Last edited:

#### GopherT

Joined Nov 23, 2012
8,012
She has a whole series of these idiot videos...

Here is another "interview"

Joined Jul 18, 2013
19,387
The Local paper just published a list from a local travel agent that consisted of questions potential travelers ask of her over the years.
The one I particularly liked was a person planning a trip to the UK, she wanted to know if they spoke English there!.
Max.

#### Raymond Genovese

Joined Mar 5, 2016
1,658
She has a whole series of these idiot videos...

Here is another "interview"

I just watched several of this "series". I don't know, but I am convinced that they are staged (possibly including some natural talent). Phrases like "hot mess", "male fantasy" and "Bimbo appeal" come to mind. Incredibly large number of views for many of them. Quite successful if that was the intent.

#### MrChips

Joined Oct 2, 2009
19,728
The Local paper just published a list from a local travel agent that consisted of questions potential travelers ask of her over the years.
The one I particularly liked was a person planning a trip to the UK, she wanted to know if they spoke English there!.
Max.
Is Scouse English? I can't understand a word of it!
My inlaws are all scousers!

Joined Jul 18, 2013
19,387
Scouse is Liverpool/Merseyside, (The Beatles Origin).
Most are of Irish descent so may have some influence on it.!
Max.

#### sarathd

Joined Mar 1, 2018
1
Three friends were in a restaurant and at the end of the meal the bill comes up to $27 including gratuities. They each give$10 to the waiter. The waiter goes to the cashier who notices that the waiter had made a mistake in tallying the tab. The correct total is $25. The cashier gives the waiter five$1 coins in change (they don't print $1 bills anymore). On the way back to the table, the waiter ponders on how he is going to split$5 three ways.
No problem, he thinks. "They think the total is $27. I will give them each$1 in change and I'll keep the remaining $2. Problem solved." Here is the math question. Each customer paid$9, times three equals $27. The waiter kept$2, equals $29. What happened to the missing$1?

(This one works best after your friends have had a few drinks.)
Forget the \$ 27.00 value that is the wrong value and recalculate in and out numbers.