- athos20145
**Posts:**96**Joined:**

... 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?

- Traden4Alpha
**Posts:**23951**Joined:**

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.

This is the stuff Gödel was taking about, it's unsolvable.

- Traden4Alpha
**Posts:**23951**Joined:**

And Douglas Adams showed that it could be the basis for interstellar travel using Bistromathics.

Lol, I must have read past that! Bistromathics

- Cuchulainn
**Posts:**61185**Joined:****Location:**Amsterdam-
**Contact:**

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

http://www.datasim.nl

Every Time We Teach a Child Something, We Keep Him from Inventing It Himself

Jean Piaget

- katastrofa
**Posts:**8772**Joined:****Location:**Alpha Centauri

The ultimate proof that Italians don't get on well with the Euro.... 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?

- athos20145
**Posts:**96**Joined:**

Absolutely!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.

- athos20145
**Posts:**96**Joined:**

lolThe ultimate proof that Italians don't get on well with the Euro.... 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?

- Traden4Alpha
**Posts:**23951**Joined:**

LOL!What's the area of this triangle?

Do you need that to 100 digits?

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.

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.

- Cuchulainn
**Posts:**61185**Joined:****Location:**Amsterdam-
**Contact:**

which one? There's 3 of them!What's the area of this triangle?

http://www.datasimfinancial.com

http://www.datasim.nl

Every Time We Teach a Child Something, We Keep Him from Inventing It Himself

Jean Piaget

http://www.datasim.nl

Every Time We Teach a Child Something, We Keep Him from Inventing It Himself

Jean Piaget

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

(There are at least five.)

(There are at least five.)

- Cuchulainn
**Posts:**61185**Joined:****Location:**Amsterdam-
**Contact:**

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

http://www.datasim.nl

Every Time We Teach a Child Something, We Keep Him from Inventing It Himself

Jean Piaget

GZIP: On