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#1 2015-10-18 19:00:33
- Divine
- Member
- Registered: 2015-10-18
- Posts: 5
Basic Operation
Question:
From four numbers, how many 4-digit codes can be made if no number is repeated in a code?
Please answer it with explanation or solutions. thank you..
Last edited by Divine (2015-10-18 19:14:21)
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#2 2015-10-18 19:13:46
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Basic Operation
What 4 numbers? 0 - 9? Can the first digit be a zero?
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 2015-10-18 19:18:24
- Divine
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- Registered: 2015-10-18
- Posts: 5
Re: Basic Operation
i dont know but these are the choices from the questionnaire, 12, 14, 18, 20 & 24.
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#4 2015-10-18 19:21:28
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Basic Operation
Then choose 24.
4 x 3 x 2 x 1
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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#5 2015-10-18 19:34:13
- Divine
- Member
- Registered: 2015-10-18
- Posts: 5
Re: Basic Operation
thank you bobby.. i guess it is 24..
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#6 2015-10-18 19:36:48
- Divine
- Member
- Registered: 2015-10-18
- Posts: 5
Re: Basic Operation
Bobby can u answer this? IF (A+B) IS THE COMMON FACTOR OF X(A+B)-(A+B), WHAT IS THE OTHER FACTOR?
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#7 2015-10-18 19:44:21
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Basic Operation
You can factor that into:
Do you see the other factor?
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 2015-10-18 20:41:59
- Divine
- Member
- Registered: 2015-10-18
- Posts: 5
Re: Basic Operation
i don't know. but these are the choices
1. x
2. x(x-b)
3. x-1
4. x(a+b)
5. x+1
my co worker answer is (a+b)squared.
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#9 2015-10-18 22:06:01
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: Basic Operation
I would go with 3) x - 1
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 2015-10-19 04:27:46
Re: Basic Operation
thank you bobby.. i guess it is 24..
How many choices do you have for the first number?
Now that the first choice is set, you can't pick that number again. So how many choices do you have for the second number? Then the third, and fourth?
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