Math Is Fun Forum

gAr

Member

Registered: 2011-01-09

Posts: 3,482

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.

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"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."

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

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)

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“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.

gAr

Member

Registered: 2011-01-09

Posts: 3,482

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."

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

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.

gAr

Member

Registered: 2011-01-09

Posts: 3,482

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."