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#1 2016-08-01 13:43:56

Mathegocart
Member
Registered: 2012-04-29
Posts: 2,226

Coin combinatorics

1. there are 4 coins with values 1,2,4, and 8. How many different amounts can be made with one or more of the 4 coins?
Each coin can ONLY BE USED ONCE.
Is it 14?
there are 4 1 coin combinations.
There are 3+2+1 2 coin combos
There are 4 3 coin combos(1,2,4),(1,4,8),(1,2,8),(2,4,8)
There is 1 4-coin combo (1,2,4,8)
thus there are 4 + 6 + 4 + 1(15 combos)
Am I right?
2.x mod 5 =1
   x mod 7 =1
  Find the least number x > 10 that satisfies these 2 equations. Is it 71?

Last edited by Mathegocart (2016-08-02 11:32:34)


The integral of hope is reality.
May bobbym have a wonderful time in the pearly gates of heaven.
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#2 2016-08-01 15:18:18

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Coin combinatorics

Hi;


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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#3 2016-08-01 16:11:10

thickhead
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Registered: 2016-04-16
Posts: 1,086

Re: Coin combinatorics


{1}Vasudhaiva Kutumakam.{The whole Universe is a family.}
(2)Yatra naaryasthu poojyanthe Ramanthe tatra Devataha
{Gods rejoice at those places where ladies are respected.}

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#4 2016-08-01 19:55:37

thickhead
Member
Registered: 2016-04-16
Posts: 1,086

Re: Coin combinatorics


{1}Vasudhaiva Kutumakam.{The whole Universe is a family.}
(2)Yatra naaryasthu poojyanthe Ramanthe tatra Devataha
{Gods rejoice at those places where ladies are respected.}

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#5 2016-08-02 11:30:23

Mathegocart
Member
Registered: 2012-04-29
Posts: 2,226

Re: Coin combinatorics

thickhead wrote:

Thickhead thanks for helping me gain a better understanding of similar combo. problems like these.


The integral of hope is reality.
May bobbym have a wonderful time in the pearly gates of heaven.
He will be sorely missed.

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#6 2016-08-02 11:32:56

Mathegocart
Member
Registered: 2012-04-29
Posts: 2,226

Re: Coin combinatorics

bobbym wrote:

Hi;

Bobbym 43 % 5 = 3 not 1


The integral of hope is reality.
May bobbym have a wonderful time in the pearly gates of heaven.
He will be sorely missed.

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#7 2016-08-02 11:58:20

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Coin combinatorics

You have 2x not x, so it is 2 x 43 = 86 which leaves a remainder of 1 when divided by 5.


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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#8 2016-08-02 12:03:56

Mathegocart
Member
Registered: 2012-04-29
Posts: 2,226

Re: Coin combinatorics

bobbym wrote:

You have 2x not x, so it is 2 x 43 = 86 which leaves a remainder of 1 when divided by 5.

bobbym that was my indicator for the 2nd question. 2.


The integral of hope is reality.
May bobbym have a wonderful time in the pearly gates of heaven.
He will be sorely missed.

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#9 2016-08-02 12:09:04

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Coin combinatorics

Oh! I thought that was 2x, I am sorry.


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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#10 2016-08-02 12:10:33

Mathegocart
Member
Registered: 2012-04-29
Posts: 2,226

Re: Coin combinatorics

bobbym wrote:

Oh! I thought that was 2x, I am sorry.

bobbym that is ok I have major oversights sometimes.


The integral of hope is reality.
May bobbym have a wonderful time in the pearly gates of heaven.
He will be sorely missed.

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#11 2016-08-02 12:14:55

bobbym
bumpkin
From: Bumpkinland
Registered: 2009-04-12
Posts: 109,606

Re: Coin combinatorics

That was one you can use the CRT on.


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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