Author Topic: permutation and combination question  (Read 1193 times)

Offline ashwinkandel

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permutation and combination question
« on: January 14, 2011, 11:58:57 am »
) Different colored pegs, each of which is painted in one and only six of the colors, white red blue Black green yellow are to be placed in four holes.

O O O O

With one peg in each hole. the pegs of the same color are identical.Calculate how many different arrangements of pegs placed in the four holes so that they are all occupied can be made from:
12 pegs, two of each colors.

Offline astarmathsandphysics

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Re: permutation and combination question
« Reply #1 on: January 19, 2011, 10:12:14 pm »
Choose 2 colours from 6 in 6C2=15 ways.
Say colour 1 and colour 2
1122
1212
1221
2211
2121
2112
 ie 6*15=90 ways