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