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# Form a dollar from n coins

Best Answer markdane22, 23 January 2013 - 03:34 PM

As this question was getting no answers, I have cheated and made the program   :

Spoiler for Program output

Go to the full post

2 replies to this topic

### #1 bonanova

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Posted 23 January 2013 - 10:04 AM

You are given n > 0 of each of the standard denomination US coins: 1¢, 5¢, 10¢, 25¢, 50¢, \$1.
Your task is then to select from them a set of n coins whose total value is exactly \$1.

Clearly, if n=1, you can do this by selecting the \$1 coin. If n=2 you select the two half-dollar coins.
But if n > 100, then every set of n coins (e.g. all the pennies) will have a total that is too large.

What is the smallest n such that it is impossible to select n coins that make exactly a dollar?
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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

### #2 markdane22

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Posted 23 January 2013 - 03:34 PM   Best Answer

As this question was getting no answers, I have cheated and made the program   :

Spoiler for Program output

Edited by markdane22, 23 January 2013 - 03:42 PM.

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### #3 bonanova

bonanova

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Posted 23 January 2013 - 04:15 PM

Hi markdane, and welcome to the Den.
That's the answer. Thanks for posting.
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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

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