[Archive!] Pure mathematics, physics, chemistry, etc.: brain-training problems not related to trade in any way - page 565

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jelizavettka:
Good girl. take a cake off the shelf, wipe off the dust and put it back. )
 
and once again the Belarus team is pulling away!
 
alsu:
and once again the Belarus team is pulling away!
so it's the women's team ))
 

How to identify a counterfeit coin (it is lighter than the others) out of eight. Using a cup scale and two weighings. ?

who knows, do not write. the way others will be interested to find the answer.

 
sergeev:


How to identify a counterfeit coin (it is lighter than the others) out of eight. Using a cup scale and two weighings. ?

who knows, don't write. the way others will be interested to find the answer.

like this though :)- 3+3=2;||2=1+1||3=2+1+(3-2)
 
LeoV:
Mathematicians have found a system for winning at roulette
Probability theorist and Santa Fe Institute professor J. Doyne Farmer, in the late seventies led a group of Eudaemons whose aim was to win roulette money from casinos, which members wanted to spend to support the scientific community.
Reminds me a lot of the Rogun GES story)))) But in general, the guys are good, they got their way.
 
sergeev:

How to identify a counterfeit coin (it is lighter than the others) out of eight. Using a cup scale and two weighings. ?

who knows, don't write. the way others will be interested to find the answer.

I know exactly how to determine whether Ukrainian hryvnias are half-denominated:
1. put the note on the table
2. take a piece of lard
3. trace the banknote around the edge

if the portrait on the banknote accompanies the lard with a look - the banknote is real!

 
LeoV:
Mathematicians have found a system for winning at roulette


Is it possible to make a bet after the roulette wheel has been unwound and the ball has been thrown in? What's the use of this analysis.

I saw a movie on the subject, the croupier was trained to throw the ball and his friends would come in and win.

 
sergeev:


How to identify a counterfeit coin (it is lighter than the others) out of eight. Using a cup scale and two weighings. ?


1st weighing on different bowls of 3 coins each:
a) if the weight is the same, the false coin is one of the 2 remaining coins, make a 2nd weighing of the 2 remaining coins-->answer--the false coin is the lighter one;
b) if the weights are different, take the light cup with three coins, make a second weighing. On different bowls of 1 coin (out of 3):
1.b)if the weight is the same, the answer--the counterfeit coin is the one that was not weighed;
2.b)if the weight is different, the answer is-- the counterfeit coin is the lighter one.
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