I seem to remember that this is given by:-
6 ! / (2 ! 4 !)
= (6) (5) / 2
= 15
2007-09-07 07:13:11
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answer #1
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answered by Como 7
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Fifteen.
If you name the people A, B, C, D, E, and F, you can have:
1. ABCD
2. ABCE
3. ABCF
4. ABDE
5. ABDF
6. ABEF
7. ACDE
8. ACDF
9. ACEF
10. ADEF
11. BCDE
12. BCDF
13. BCEF
14. BDEF
15. CDEF
I started with ABCD, then changed the last person to E, then to F. Then I backed up to the third person and changed them to D, but I didn't start with ABDD, because that would have put the same person on the committee twice, and I didn't go back to ABDC, because that's just a rearrangement of ABCD. I just proceeded from there, replacing members of the committee until I'd included them all.
Not very algebraic, I know, but it works. If you want to do it algebraically, you have to use the equation for the number of combinations possible from a set.
C = [n(n-1)(n-2)(n-3)... to k factors] / k!
Where n is the number of people available (6 in this case) and k is the number of people in each committee (4). k! is k factorial, or the number you get when you multiply all the whole numbers between 1 and k. For example, if k = 4, then:
k! = 4! = 1 x 2 x 3 x 4 = 24
So the total number of combinations is:
C = [(6)(6-1)(6-2)(6-3)] / 24
C = [(6)(5)(4)(3)] / 24
C = 360 / 24
C = 15
There ya go.
2007-09-03 09:09:12
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answer #2
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answered by Lucas C 7
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You can simplify this by saying that choosing 4 to go on the committee is the same as choosing 2 to be left out.
The first person can be chosen in 6 ways.
The second person can be chosen in 5 ways.
That gives 30 possibilities, but they will not all be different, as you could have chosen first A and then B, or first B and then A in every case.
Divide the 30 by 2 to get 15 as the answer.
In formal notation that is 6C4 or C(6,4)
= 6! / ( 2! 4! )
= 6 * 5 / 2
= 15.
2007-09-03 08:54:21
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answer #3
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answered by Anonymous
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To calculate the number of ways to choose r of n objects, without repetition, use the formula (n!)/r!(n-r)!
In your example: 6!/2!(6-2)! = 1*2*3*4*5*6/1*2*(1*2*3*4)
= 5*6/2 = 15
ADDENDUM
robertonereo missed
1345
1346
1356
1456
2456
2007-09-03 08:56:49
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answer #4
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answered by Anonymous
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I HATE ALGEBRA! im in 8th grade and already in algebra 2 that's hilarious because of the fact i didnt even comprehend algebra I or maybe pre algebra. it doesnt make any experience to me and its sooo pointless no ones even gonna use this in every day existence heavily, i failed it each grading quarter even although i stayed after class plenty and that i've got been given help particularly much every day
2016-11-14 02:24:12
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answer #5
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answered by ? 4
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Persons = 1 2 3 4 5 6
You may have:
1) 1234
2) 1235
3) 1236
4) 1245
5) 1246
6) 1256
7) 2345
8) 2346
9) 2356
10) 3456
10 distinct committees
2007-09-03 08:50:39
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answer #6
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answered by robertonereo 4
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Thats 6C4=15
2007-09-03 08:48:24
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answer #7
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answered by rock_bottom456 2
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