A secretary differentiates Â…files by a variety of color combinations. If she uses 4 different colors, and marks each fiÂ…le with 1, 2, or 3 of the colors, how many different color combinations can she generate?
(A) 4
(B) 12
(C) 14
(D) 15
(E) 24
combinations /600-650
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Last edited by Night reader on Sat Dec 04, 2010 7:44 pm, edited 1 time in total.
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Let the Colors Be A,B,C and D.
Three possibilities.
1 Color to Identify each file. - Each color to identify every file. 4 Ways. (4C1 Ways)
2 Colors to Identify each file -
Here the order of the color matters. Since order matters we have to proceed with permutation.
4P2 ways= 12 ways
(AB,BA, CD,DC, BC,CB,AD,DA,AC,CA,BD,DA)
3 Colors to Identify each file -
Here also the order of the color matters. Since order matters we have to proceed with permutation again.
4P3 ways = 24 ways
(ABC - This color combination can be arranged in 3! ways = 6 Ways)
(BCD - This color combination can be arranged in 3! Ways = 6 ways)
(ABD - This color combination can be arranged in 3! Ways = 6 ways)
(ACD - This color combination can be arranged in 3! ways = 6 ways)
Summing it up 24+12+4 = 40 Ways.
I get atleast 40 ways.
I dont know what else i am missing.
Can anybody help??
Thanks
Three possibilities.
1 Color to Identify each file. - Each color to identify every file. 4 Ways. (4C1 Ways)
2 Colors to Identify each file -
Here the order of the color matters. Since order matters we have to proceed with permutation.
4P2 ways= 12 ways
(AB,BA, CD,DC, BC,CB,AD,DA,AC,CA,BD,DA)
3 Colors to Identify each file -
Here also the order of the color matters. Since order matters we have to proceed with permutation again.
4P3 ways = 24 ways
(ABC - This color combination can be arranged in 3! ways = 6 Ways)
(BCD - This color combination can be arranged in 3! Ways = 6 ways)
(ABD - This color combination can be arranged in 3! Ways = 6 ways)
(ACD - This color combination can be arranged in 3! ways = 6 ways)
Summing it up 24+12+4 = 40 Ways.
I get atleast 40 ways.
I dont know what else i am missing.
Can anybody help??
Thanks
Tried solving for both combos and for perms because was confused about the answer choices:
I'm getting 14 if order doesn't matter
If order matters I'm getting the same as Junegmat with 40
Don't think I missed anything....
OA?
I'm getting 14 if order doesn't matter
If order matters I'm getting the same as Junegmat with 40
Don't think I missed anything....
OA?
- goyalsau
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You are right, Even i am also getting 14,rros0770 wrote:Tried solving for both combos and for perms because was confused about the answer choices:
I'm getting 14 if order doesn't matter
If order matters I'm getting the same as Junegmat with 40
Don't think I missed anything....
OA?
4C1 = 4
4C2 = 6
4C3 = 4
In all 14
I don't think sequence will matter over here.........
Saurabh Goyal
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- jaymw
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What's the source of this question?
Usually the stem of a question should indicate whether order matters or not. This one sounds as if it doesn't (the word combinations is a hint, though).
Also, I am very confused by the answer choices. This might be just a technicality, but usually the answer choices (provided they consist of numbers) are presented in an ascending order!
Usually the stem of a question should indicate whether order matters or not. This one sounds as if it doesn't (the word combinations is a hint, though).
Also, I am very confused by the answer choices. This might be just a technicality, but usually the answer choices (provided they consist of numbers) are presented in an ascending order!
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you are all right, it was mistyped - correct answer is C 14jaymw wrote:What's the source of this question?
Usually the stem of a question should indicate whether order matters or not. This one sounds as if it doesn't (the word combinations is a hint, though).
Also, I am very confused by the answer choices. This might be just a technicality, but usually the answer choices (provided they consist of numbers) are presented in an ascending order!