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#1 2013-09-02 05:51:04

mathstudent2000
Member
Registered: 2013-07-26
Posts: 79

mathcounts/amc problems

1. How many sets of 3 primes sum to 20?

2. An old book listed that 72 turkeys were bought for $\square.\square\square each, at a total cost of $\square 67.9\square. What was the cost of each turkey, if each \square stands for a digit that was unreadable in the old book?

Note: The \square digits are not all the same.

3. A number has three distinct digits. The sum of the digits equals the product of the digits. How many three-digit numbers satisfy this condition?


Genius is one percent inspiration and ninety-nine percent perspiration

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#2 2013-09-02 07:24:58

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,018

Re: mathcounts/amc problems

Hi



“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 2013-09-02 09:44:33

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 107,133

Re: mathcounts/amc problems

Hi;

2)

What does \square mean?

The only solution to the problem as you have written it is:

72 x 5.11 = 367.92


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#4 2013-09-02 10:59:46

anonimnystefy
Real Member
From: Harlan's World
Registered: 2011-05-23
Posts: 16,018

Re: mathcounts/amc problems

Yes, I agree. That is the only possibility.


“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 2013-09-02 12:38:24

mathstudent2000
Member
Registered: 2013-07-26
Posts: 79

Re: mathcounts/amc problems

ok

it means a box in which a unknown number is placed


Genius is one percent inspiration and ninety-nine percent perspiration

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#6 2013-09-02 12:44:27

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 107,133

Re: mathcounts/amc problems

It is the only answer, it was derived in 2 ways.


In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

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#7 2013-09-02 12:45:51

mathstudent2000
Member
Registered: 2013-07-26
Posts: 79

Re: mathcounts/amc problems

ok got it


Genius is one percent inspiration and ninety-nine percent perspiration

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