SERVING THE QUANTITATIVE FINANCE COMMUNITY

 
User avatar
athos20145
Topic Author
Posts: 96
Joined: July 14th, 2002, 3:00 am

I can't solve this ...

October 28th, 2016, 7:21 pm

... 3 people go to a restaurant. They eat and the bill amounts to 30 euros. They decide to share the bill so they pay 10 euros each. The restaurant owner gives them a discount of 5 euros, and he returns 5 euros in 1 euro coins. The 3 diners decide to take 1 euro each, so spending 9 euros each, and they leave a tip of 2 euros to the waiter. The diners spent 9 euros times 3 = 27 euros plus 2 euros tip for a total of 29 euros. Where has the missing euro gone?
 
User avatar
Traden4Alpha
Posts: 23951
Joined: September 20th, 2002, 8:30 pm

Re: I can't solve this ...

October 28th, 2016, 8:11 pm

There's no missing Euro because the total is NOT 27+2. Instead it's 27 put in by the diners of which the restaurant took 25, leaving 2 for the waiter.
 
User avatar
outrun
Posts: 4573
Joined: April 29th, 2016, 1:40 pm

Re: I can't solve this ...

October 28th, 2016, 8:13 pm

This is the stuff Gödel was taking about, it's unsolvable. 
 
User avatar
Traden4Alpha
Posts: 23951
Joined: September 20th, 2002, 8:30 pm

Re: I can't solve this ...

October 28th, 2016, 8:30 pm

And Douglas Adams showed that it could be the basis for interstellar travel using Bistromathics.
 
User avatar
outrun
Posts: 4573
Joined: April 29th, 2016, 1:40 pm

Re: I can't solve this ...

October 28th, 2016, 8:34 pm

Lol, I must have read past that! Bistromathics
 
User avatar
Cuchulainn
Posts: 61185
Joined: July 16th, 2004, 7:38 am
Location: Amsterdam
Contact:

Re: I can't solve this ...

October 29th, 2016, 9:10 pm

Try doing the same exercise with 20% included.
http://www.datasimfinancial.com
http://www.datasim.nl

Every Time We Teach a Child Something, We Keep Him from Inventing It Himself
Jean Piaget
 
User avatar
katastrofa
Posts: 8772
Joined: August 16th, 2007, 5:36 am
Location: Alpha Centauri

Re: I can't solve this ...

October 29th, 2016, 9:26 pm

... 3 people go to a restaurant. They eat and the bill amounts to 30 euros. They decide to share the bill so they pay 10 euros each. The restaurant owner gives them a discount of 5 euros, and he returns 5 euros in 1 euro coins. The 3 diners decide to take 1 euro each, so spending 9 euros each, and they leave a tip of 2 euros to the waiter. The diners spent 9 euros times 3 = 27 euros plus 2 euros tip for a total of 29 euros. Where has the missing euro gone?
The ultimate proof that Italians don't get on well with the Euro.
 
User avatar
athos20145
Topic Author
Posts: 96
Joined: July 14th, 2002, 3:00 am

Re: I can't solve this ...

October 30th, 2016, 5:03 pm

There's no missing Euro because the total is NOT 27+2.  Instead it's 27 put in by the diners of which the restaurant took 25, leaving 2 for the waiter.
Absolutely!
 
User avatar
athos20145
Topic Author
Posts: 96
Joined: July 14th, 2002, 3:00 am

Re: I can't solve this ...

October 30th, 2016, 5:04 pm

... 3 people go to a restaurant. They eat and the bill amounts to 30 euros. They decide to share the bill so they pay 10 euros each. The restaurant owner gives them a discount of 5 euros, and he returns 5 euros in 1 euro coins. The 3 diners decide to take 1 euro each, so spending 9 euros each, and they leave a tip of 2 euros to the waiter. The diners spent 9 euros times 3 = 27 euros plus 2 euros tip for a total of 29 euros. Where has the missing euro gone?
The ultimate proof that Italians don't get on well with the Euro.
lol
 
User avatar
outrun
Posts: 4573
Joined: April 29th, 2016, 1:40 pm

Re: I can't solve this ...

April 23rd, 2017, 8:24 pm

What's the area of this triangle?
Image
 
User avatar
Traden4Alpha
Posts: 23951
Joined: September 20th, 2002, 8:30 pm

Re: I can't solve this ...

April 23rd, 2017, 11:32 pm

What's the area of this triangle?
Image
LOL!

Do you need that to 100 digits?
 
User avatar
wileysw
Posts: 593
Joined: December 9th, 2006, 6:13 pm

Re: I can't solve this ...

April 24th, 2017, 6:22 pm

this problem is due to Vladimir I. Arnold, who claimed that he had seen it in a standard American examination and used it as an example to criticize American math education.

such triangle does not exist.  one way to see it is that the vertex of the right angle lies on a circle with the hypotenuse as a diameter, thus the corresponding altitude is at most half of the hypotenuse, which is 5 in this case.

this of course assumes Euclidean geometry.  it's not difficult to embed such triangle into e.g., a 2-sphere, though it would be beyond Arnold's point as he was referring to children from age 5 to 15.
 
User avatar
Cuchulainn
Posts: 61185
Joined: July 16th, 2004, 7:38 am
Location: Amsterdam
Contact:

Re: I can't solve this ...

April 24th, 2017, 6:33 pm

What's the area of this triangle?
Image
which one? There's 3 of them!
http://www.datasimfinancial.com
http://www.datasim.nl

Every Time We Teach a Child Something, We Keep Him from Inventing It Himself
Jean Piaget
 
User avatar
Paul
Posts: 10093
Joined: July 20th, 2001, 3:28 pm

Re: I can't solve this ...

April 24th, 2017, 6:36 pm

What else is there to do while queuing for bread other than to criticise American mathematics education?

(There are at least five.)
 
User avatar
Cuchulainn
Posts: 61185
Joined: July 16th, 2004, 7:38 am
Location: Amsterdam
Contact:

Re: I can't solve this ...

April 24th, 2017, 7:30 pm

Now I see one more! 
http://www.datasimfinancial.com
http://www.datasim.nl

Every Time We Teach a Child Something, We Keep Him from Inventing It Himself
Jean Piaget
ABOUT WILMOTT

PW by JB

Wilmott.com has been "Serving the Quantitative Finance Community" since 2001. Continued...


Twitter LinkedIn Instagram

JOBS BOARD

JOBS BOARD

Looking for a quant job, risk, algo trading,...? Browse jobs here...


GZIP: On