Q27 of 30 Page 7

Find the number of ways of selecting 9 balls from 6 red balls, 5 white balls and 5 blue balls if each selection consists of 3 balls of each colour.


Three red balls can be selected out of 6 red balls in 6C3 ways.

Similarly, three white balls can be selected out of 6 white balls in 5C3 ways. And three black balls can be selected out of 5 blue balls in 5C3 ways. The number ways of selecting 9 balls = 6C3 × 5C3 × 5C3

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