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## #1 2013-10-10 23:13:05

gAr
Member
Registered: 2011-01-09
Posts: 3,479

### Find the mass of the coins

There are 13 piles, each having 4 coins. One of the piles contains 4 counterfeit coins.
The genuine coin's 'x' grams (a positive integer), and the counterfeit coin's x+Δ grams (Δ is a non-­zero
real number strictly between ­-5 and +5). Having a precise digital scale, determine x, Δ, and the pile containing the counterfeit coins using the scale only twice.

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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## #2 2013-10-11 10:31:22

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,037

### Re: Find the mass of the coins

I think I have it! I'll edit this post to include the answer:

Last edited by anonimnystefy (2013-10-11 10:40:57)

Here lies the reader who will never open this book. He is forever dead.
Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

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## #3 2013-10-11 15:53:58

gAr
Member
Registered: 2011-01-09
Posts: 3,479

### Re: Find the mass of the coins

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

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## #4 2013-10-11 21:40:26

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,037

### Re: Find the mass of the coins

Thanks! I like this puzzle a lot!

Here lies the reader who will never open this book. He is forever dead.
Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

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## #5 2013-10-11 22:45:36

gAr
Member
Registered: 2011-01-09
Posts: 3,479

### Re: Find the mass of the coins

You're welcome!

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

Offline