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Saturday, December 13, 2008

Q) How many groups can be made from 5 different green balls, 4 different blue balls and 3 different red balls, if at least 1 green ball and 1 blue ball are to be included?

A)
Choose 1 green ball and 1 blue ball, + extra balls [ 0 to 10 in number]
5C1 . 4C1 . (10C0 + 10C1 + 10C2 ....10C10)
= 5*4* (1+1)^10
= (20). 2^10 groups

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